Engine Controls - System & Component Testing - V6 & V8: Other Toyota 4Runner IV

ENGINE CONTROL SYSTEM

For engine control system component locations (Scheme 168)- (Scheme 180).

Scheme 168

Scheme 169

Scheme 170

Scheme 171

Scheme 172

Scheme 173

Scheme 174

Scheme 175

Scheme 176

Scheme 177

Scheme 178

Scheme 179

Scheme 180

ENGINE CONTROL MODULE

For ECM location (Scheme 181)- (Scheme 189).

Scheme 181

Scheme 182

Scheme 183

Scheme 184

Scheme 185

Scheme 186

Scheme 187

Scheme 188

Scheme 189

Sienna

Note. Following procedure should be performed if power sliding door system does not operate properly under the following conditions: battery is disconnected and reconnected, battery is discharged and recharged, or open power sliding door warning light remains on even with power sliding doors closed.

1. If power sliding door system does not operate properly and open power sliding door warning light remains on, even with power sliding doors closed, go to next step. If power sliding door system does not operate properly after battery is disconnected and reconnected or battery is discharged and recharged, go to step 4 .
2. Ensure power sliding door main switch is in OFF position. Power sliding door main switch is located on driver's side of instrument panel, just to the left of steering column and is marked as PWR DOOR OFF. Disconnect battery for one minute and then reconnect the battery. Close power sliding door by hand.
3. Turn on power sliding door system by placing power sliding door main switch in the ON position. Wait 5 seconds and then go to next step.
4. Ensure power sliding door main switch is in ON position if not previously done. Power sliding door main switch is located on driver's side of instrument panel, just to the left of steering column and is marked as PWR DOOR OFF. Open one of the power sliding doors by using the power sliding door control switch. Power sliding door control switches are located near center of instrument panel, just below the stereo.
5. Wait 3 seconds after power sliding door stops at the fully open position and then close power sliding door by using power sliding door control switch on instrument panel or by using remote keyless entry transmitter.
6. Wait 3 seconds after power sliding door stops at the fully closed position and then repeat steps 4 and 5 .

Camry

Note. Following procedure should be performed if battery is disconnected and reconnected, or battery is discharged and recharged to provide proper automatic operation and jam protection operation of power sun roof.

1. Ensure ignition is on. Depress and hold TILT UP side of power sun roof switch until power sun roof tilts all the way upward and then tilts downward a little. Power sun roof switch is located on headliner, just in front of power sun roof.
2. Check for proper operation of open/closing and tilt up/down function for power sun roof using power sun roof switch. Power sun roof should operate anytime ignition is on, or for 43 seconds after ignition is off provided both front doors are closed. It will stop operating if any front door is opened. Depressing SLIDE OPEN side of power sun roof switch for one second should open power sun roof.
3. Depressing TILT UP side of power sun roof switch for one second should close power sun roof. To tilt power sun roof upward, depress and hold TILT UP side of power sun roof switch for one second. To tilt power sun roof downward, depress and hold SLIDE OPEN side of power sun roof switch for one second.

ACOUSTIC CONTROL INDUCTION SYSTEM

Note. Acoustic Control Induction System (ACIS) may also be referred to as Intake Air Control Valve (IACV) system.

Avalon & Sienna

1. Acoustic Control Induction System (ACIS) uses 2 intake air control valves, one on end of air intake chamber and one near throttle bodies. (Scheme 190) Intake air control valve on end of air intake chamber may also be referred to as No. 2 intake air control valve. Intake air control valve near throttle bodies may also be referred to as No. 1 intake air control valve. Operation of actuator valve for each intake air control valve should be checked. Using 3-way connector, connect vacuum gauge in vacuum line to actuator valve for appropriate intake air control valve. (Scheme 191) Actuator valve may also be referred to as the actuator.
2. Start engine. With engine idling, ensure no vacuum reading is obtained. Fully open throttle and ensure vacuum reading momentarily reads approximately 7.9 in. Hg and actuator valve rod pulls out. If actuator valve rod does not pull out, go to next step. If actuator valve rod pulls out, system is operating properly.
3. Disconnect vacuum hose from appropriate actuator valve. Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator valve. Ensure actuator valve rod moves and does not return to original position for at least one minute. If actuator valve does not operate properly, replace intake air control valve assembly. See «INTAKE AIR CONTROL VALVE»(ref-151984-S15675799392003010900000) under AIR INDUCTION SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article.
4. If actuator valve operates properly, reconnect vacuum hose. Check ACIS control circuit. See «ACOUSTIC CONTROL INDUCTION SYSTEM CONTROL CIRCUIT»(ref-151979-S14438788402003010900000) under COMPUTERIZED ENGINE CONTROLS.

Scheme 190

Scheme 191

Camry (Up To Jan. 2003 Production)

1. Acoustic Control Induction System (ACIS) uses intake air control valve on end of air intake chamber. Using 3-way connector, connect vacuum gauge in vacuum line to actuator valve. Actuator valve is located at end of air intake chamber and may also be referred to as the actuator. (Scheme 192)
2. Connect Toyota hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 384) Start engine. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate intake air control valve Vacuum Switching Valve (VSV) and note vacuum reading. Intake air control valve VSV may also be referred to as ACIS VSV. When intake air control valve VSV is off, ensure no vacuum reading is obtained. When intake air control valve VSV is on, ensure vacuum reading momentarily reads approximately 7.9 in. Hg and actuator valve rod pulls inward. If actuator valve rod does not pull inward, go to next step. If actuator valve rod pulls inward, go to step 4.
3. Disconnect vacuum hose from actuator valve. Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator valve. Ensure actuator valve rod pulls inward and remains pulled inward for at least one minute. If actuator valve operates properly, reconnect vacuum hose and go to next step. If actuator valve does not operate properly, replace intake air control valve assembly. See «INTAKE AIR CONTROL VALVE»(ref-151984-S15675799392003010900000) under AIR INDUCTION SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article.
4. Ensure transaxle is in park. While monitoring data monitor on hand-held tester, check that intake air control valve VSV turns on and off in relation to throttle opening percentage and engine RPM. (Scheme 193) Value in illustration is only for reference, as throttle opening percentage may operate diversely depending on operating conditions. Remove hand-held tester and reconnect vacuum hose. If system operates properly, test is complete. If system does not operate as specified, check ACIS control circuit. See «ACOUSTIC CONTROL INDUCTION SYSTEM CONTROL CIRCUIT»(ref-151979-S14438788402003010900000) under COMPUTERIZED ENGINE CONTROLS.

Scheme 192

Scheme 193

Camry (Jan. 2003 & Later Production)

1. Acoustic Control Induction System (ACIS) uses 2 intake air control valves, one on end of air intake chamber and one near throttle body. Intake air control valve on end of air intake chamber may also be referred to as No. 2 intake air control valve. Intake air control valve near throttle body may also be referred to as No. 1 intake air control valve. Operation of actuator valve for each intake air control valve should be checked. Using 3-way connector, connect vacuum gauge in vacuum line to actuator valve for appropriate intake air control valve. (Scheme 194) Actuator valve may also be referred to as the actuator.
2. Connect Toyota hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 384) Start engine. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate intake air control valve Vacuum Switching Valve (VSV) and note vacuum reading. Intake air control valve VSV may also be referred to as ACIS VSV. When intake air control valve VSV is off, ensure no vacuum reading is obtained. When intake air control valve VSV is on, ensure vacuum reading momentarily reads approximately 7.9 in. Hg and actuator valve rod pulls inward. If actuator valve rod does not pull inward, go to next step. If actuator valve rod pulls inward, go to step 4.
3. Disconnect vacuum hose from actuator valve. Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator valve. Ensure actuator valve closes and remains closed for at least one minute. If actuator valve operates properly, reconnect vacuum hose and go to next step. If actuator valve does not operate properly, replace intake air control valve assembly. See «INTAKE AIR CONTROL VALVE»(ref-151984-S15675799392003010900000) under AIR INDUCTION SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article.
4. Ensure transaxle is in park. While operating accelerator pedal, monitor data monitor on hand-held tester and check open and closed status of No. 1 and No. 2 intake air control valves in relation to throttle opening percentage and engine RPM. (Scheme 195) Value in illustration is only for reference, as throttle valve open position varies by engine speed. Remove hand-held tester and reconnect vacuum hose. If system operates properly, test is complete. If system does not operate as specified, check ACIS control circuit. See «ACOUSTIC CONTROL INDUCTION SYSTEM CONTROL CIRCUIT»(ref-151979-S14438788402003010900000) under COMPUTERIZED ENGINE CONTROLS.

Scheme 194

Scheme 195

Camry Solara

1. Acoustic Control Induction System (ACIS) uses intake air control valve on end of air intake chamber. Using 3-way connector, connect vacuum gauge in vacuum line to actuator valve. (Scheme 196) Actuator valve is located at end of air intake chamber and may also be referred to as the actuator.
2. Start engine. With engine idling, ensure no vacuum reading is obtained. Fully open throttle and ensure vacuum reading momentarily reads approximately 7.9 in. Hg and actuator valve rod pulls out. If actuator valve rod does not pull out, go to next step. If actuator valve rod pulls out, system is operating properly.
3. Disconnect vacuum hose from actuator valve. Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator valve. Ensure actuator valve rod pulls out and remains pulled out for at least one minute. (Scheme 197) If actuator valve operates properly, reconnect vacuum hose. Check ACIS control circuit. See «ACOUSTIC CONTROL INDUCTION SYSTEM CONTROL CIRCUIT»(ref-151979-S14438788402003010900000) under COMPUTERIZED ENGINE CONTROLS. If actuator valve does not operate properly, replace intake air control valve assembly. See «INTAKE AIR CONTROL VALVE»(ref-151984-S15675799392003010900000) under AIR INDUCTION SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article.

Scheme 196

Scheme 197

Highlander

1. Acoustic Control Induction System (ACIS) uses 2 intake air control valves, one on end of air intake chamber and one near throttle bodies. (Scheme 190) Intake air control valve on end of air intake chamber may also be referred to as No. 2 intake air control valve. Intake air control valve near throttle bodies may also be referred to as No. 1 intake air control valve. Operation of actuator valve for each intake air control valve should be checked. Using 3-way connector, connect vacuum gauge in vacuum line to actuator valve for appropriate intake air control valve. (Scheme 191) Actuator valve may also be referred to as the actuator.
2. Connect Toyota hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 396) Start engine. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate intake air control valve No. 1 and 2 Vacuum Switching Valves (VSV) and note vacuum reading. Intake air control valve VSVs may also be referred to as ACIS VSVs. When each intake air control valve VSV is off, ensure no vacuum reading is obtained. When each intake air control valve VSV is on, ensure vacuum reading momentarily reads approximately 7.9 in. Hg and actuator valve rod moves. If actuator valve rod does not move, go to next step. If actuator valve rod moves, go to step 4.
3. Disconnect vacuum hose from actuator valve. Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator valve. Ensure actuator valve rod moves and does not return to original position for at least one minute. If actuator valve operates properly, reconnect vacuum hose and go to next step. If actuator valve does not operate properly, replace intake air control valve assembly. See «INTAKE AIR CONTROL VALVE»(ref-151984-S15675799392003010900000) under AIR INDUCTION SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article.
4. Ensure transaxle is in park. While monitoring data monitor on hand-held tester, check that intake air control valve No. 1 and 2 VSVs turn on and off in relation to throttle opening percentage and engine RPM. (Scheme 198) Value in illustration is only for reference, as throttle opening percentage may operate diversely depending on operating conditions. Shut engine off. Remove hand-held tester and reconnect vacuum hose. If system operates properly, test is complete. If system does not operate as specified, check ACIS control circuit. See «ACOUSTIC CONTROL INDUCTION SYSTEM CONTROL CIRCUIT»(ref-151979-S14438788402003010900000) under COMPUTERIZED ENGINE CONTROLS.

Scheme 198

4Runner 4.0L

1. Acoustic Control Induction System (ACIS) uses intake air control valve on end of air intake chamber. Using 3-way connector, connect vacuum gauge in vacuum line to actuator valve. (Scheme 199) Actuator valve is located at end of air intake chamber and may also be referred to as the actuator.
2. Connect Toyota hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 245) Start engine. Select ACTIVE TEST MODE on hand-held tester. Using hand-held tester manufacturer's instructions, activate intake air control valve Vacuum Switching Valve (VSV) and note vacuum reading. Intake air control valve VSV may also be referred to as ACIS VSV. When intake air control valve VSV is off, engine is idling and accelerator pedal below 60% of accelerator opening angle, ensure vacuum reading momentarily reads approximately 11.8 in. Hg and actuator valve rod is pulled out. When each intake air control valve VSV is on, accelerator pedal to 60% of accelerator opening angle and engine speed is above 4,700 RPM, ensure no vacuum reading is obtained and actuator rod returns to original position. If actuator valve rod moves, system is operating properly.
3. Disconnect vacuum hose from actuator valve. Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator valve. Ensure actuator valve rod moves and does not return to original position for at least one minute. If actuator valve operates properly, reconnect vacuum hose and go to next step. If actuator valve does not operate properly, replace intake air control valve.
4. If actuator valve operates properly, reconnect vacuum hose. Check ACIS control circuit. See «ACOUSTIC CONTROL INDUCTION SYSTEM CONTROL CIRCUIT»(ref-151979-S14438788402003010900000) under COMPUTERIZED ENGINE CONTROLS.

Scheme 199

For Air Intake Control System (AICS) testing procedure, see AIR INTAKE CONTROL SYSTEM under COMPUTERIZED ENGINE CONTROLS.

ELECTRONIC THROTTLE CONTROL SYSTEM

Note. Electronic Throttle Control System (ETCS) may also be referred to as Electronic Throttle Control System-Intelligent (ETCS-I or ETCS-i).

Camry, Land Cruiser, Sequoia, Tacoma With ETCS, Tundra & 4Runner

For testing of throttle body and components, see THROTTLE BODY under IDLE CONTROL SYSTEMS.

ACOUSTIC CONTROL INDUCTION SYSTEM CONTROL CIRCUIT

Note. Acoustic Control Induction System (ACIS) control circuit may also be referred to as Intake Air Control Valve (IACV) system control circuit.

Avalon, Camry, Camry Solara, Highlander & Sienna

1. Remove "V" bank cover located on top of engine. (Scheme 200)- (Scheme 204).
2. Disconnect electrical connector and vacuum hoses from intake air control valve Vacuum Switching Valve (VSV). (Scheme 200)- (Scheme 204). On Avalon, Camry (Jan. 2003 and later production models), Highlander and Sienna, 2 intake air control valve VSVs are used. Intake air control valve No. 1 VSV is for intake air control valve near throttle bodies which may also be referred to as No. 1 intake air control valve. Intake air control valve No. 2 VSV is for intake air control valve on end of air intake chamber which may also be referred to as No. 2 intake air control valve. On all models, it may be necessary to remove emission control valve set which contains various vacuum switching valves for access to intake air control valve VSV.
3. Using ohmmeter, check that continuity exists between electrical terminals on intake air control valve VSV and that resistance is 33-39 ohms at 68°F (20°C). If continuity exists and resistance is within specification, go to next step. If no continuity exists or resistance is not within specification, replace intake air control valve VSV.
4. Using ohmmeter, ensure no continuity exists between each electrical terminal and body of intake air control valve VSV. If continuity does not exist between electrical terminal and body of intake air control valve VSV, go to next step. If continuity exists between electrical terminal and body of intake air control valve VSV, replace intake air control valve VSV.
5. Apply air pressure to port "B" on intake air control valve VSV. Ensure air flows from the filter and not from port "A". Perform STEP 1 in illustration. (Scheme 205)
6. Apply battery voltage and ground to electrical terminals on intake air control valve VSV. Apply air pressure to port "B" on intake air control valve VSV. Ensure air flows from port "A" and not from the filter. Perform STEP 2 in illustration. (Scheme 205) If intake air control valve VSV operates properly, reinstall intake air control valve VSV and go to next step. If intake air control valve VSV does not operate properly, replace intake air control valve VSV and recheck system operation.
7. On Avalon, Camry, Camry Solara and Highlander, remove glove box for access to Engine Control Module (ECM). On Sienna, remove passenger's side lower instrument panel cover for access to Engine Control Module (ECM). On all models, for illustration of ECM location, see «ENGINE CONTROL MODULE»(ref-151979-S42582171412003100300000) under COMPONENT LOCATIONS. Note ECM electrical connector terminal identification. (Scheme 250)- (Scheme 265) and (Scheme 279).
8. Turn ignition on. Using voltmeter, check voltage between body ground and specified ECM terminal(s). See «ECM TERMINAL IDENTIFICATION FOR INTAKE AIR CONTROL VALVE VSV»(ref-151979-S36409743442003010900000) table. This is the wire from intake air control valve VSV to ECM. Intake air control valve VSV may also be referred to as ACIS VSV. Voltage should be 9-14 volts.
9. If voltage is within specification, go to next step. If voltage is not within specification, check for open and short in wiring harness and connectors between EFI main relay, intake air control valve VSV and ECM. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment and may also be referred to as EFI relay. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS.
10. On Avalon, Camry Solara and Sienna, go to next step. On Camry and Highlander, go to step 14.
11. Disconnect hoses from vacuum tank. Vacuum tank is located near driver's side front corner of engine compartment, below battery tray. Apply air pressure to port "B" on vacuum tank. Ensure air flows from port "A". Perform STEP 1 in illustration. (Scheme 206)
12. Apply air pressure to port "A". Ensure air does not flow from port "B". Perform STEP 2 in illustration. (Scheme 206)
13. Plug port "B". Using vacuum pump, apply 7.9 in. Hg of vacuum to port "A". Perform STEP 3 in illustration. (Scheme 206) Ensure vacuum reading will hold for at least one minute. If vacuum tank is okay, reconnect vacuum hoses and go to step 16. If vacuum tank is defective, replace vacuum tank and recheck system operation.
14. Disconnect hoses from vacuum tank. Vacuum tank is located on upper cap on air cleaner assembly. (Scheme 201), (Scheme 202) and (Scheme 204). Note ports on vacuum tank. (Scheme 207) Plug port "C" on vacuum tank. Apply air pressure to port "B". Ensure air flows from port "A".
15. Plug port "C". Apply air pressure to port "A". Ensure air does not flow from port "B". Plug ports "A" and "C". On Camry, using vacuum pump, apply 18 in. Hg of vacuum to port "B". On Highlander, using vacuum pump, apply 24 in. Hg of vacuum to port "B". On all models, ensure vacuum reading will hold for at least one minute. If vacuum tank is okay, reconnect vacuum hoses and go to next step. If vacuum tank is defective, replace vacuum tank or upper cap on air cleaner assembly as necessary and recheck system operation.
16. On all models, check ECM ground circuit. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If ECM ground circuit is okay, replace ECM. If ECM is replaced and vehicle is equipped with engine immobilizer system, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see «COMPUTER RELEARN PROCEDURES - TOYOTA»(ref-158393) article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

Scheme 200

Scheme 201

Scheme 202

Scheme 203

Scheme 204

Scheme 205

Scheme 206

Scheme 207

ECM TERMINAL IDENTIFICATION FOR INTAKE AIR CONTROL VALVE VSV

1. Disconnect electrical connector and vacuum hoses from intake air control valve Vacuum Switching Valve (VSV). Intake air control valve VSV may also be referred to as VSV No. 1. Remove intake air control valve VSV. (Scheme 208)
2. Using ohmmeter, check that continuity exists between electrical terminals on intake air control valve VSV and that resistance is 33-39 ohms at 68°F (20°C). If continuity exists and resistance is within specification, go to next step. If no continuity exists or resistance is not within specification, replace intake air control valve VSV.
3. Using ohmmeter, ensure no continuity exists between each electrical terminal and body of intake air control valve VSV. If continuity does not exist between electrical terminal and body of intake air control valve VSV, go to next step. If continuity exists between electrical terminal and body of intake air control valve VSV, replace intake air control valve VSV.
4. Apply air pressure to port "B" on intake air control valve VSV. Ensure air flows from the filter and not from port "A". Perform STEP 1 in illustration. (Scheme 205)
5. Apply battery voltage and ground to electrical terminals on intake air control valve VSV. Apply air pressure to port "B" on intake air control valve VSV. Ensure air flows from port "A" and not from the filter. Perform STEP 2 in illustration. (Scheme 205) If intake air control valve VSV operates properly, reinstall intake air control valve VSV and go to next step. If intake air control valve VSV does not operate properly, replace intake air control valve VSV and recheck system operation.
6. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «ENGINE CONTROL MODULE»(ref-151979-S42582171412003100300000) under COMPONENT LOCATIONS. Note ECM electrical connector terminal identification. (Scheme 302)
7. Turn ignition on. Using voltmeter, check voltage between terminal 15 at ECM electrical connector E4 and No. 1 at ECM electrical connector E1 These are AICV and E1 terminals at ECM. When engine speed is between 2,200 and 4,100 RPM and throttle valve opening is more than 60 degrees, then voltage between two terminals should be 9-14 volts.
8. If voltage is within specification, go to next step. If voltage is not within specification, check for open and short in wiring harness and connectors between EFI main relay, intake air control valve VSV and ECM. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment and may also be referred to as EFI relay. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS.
9. Check ECM ground circuit. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. If ECM ground circuit is okay, replace ECM. If ECM is replaced and vehicle is equipped with engine immobilizer system, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see «COMPUTER RELEARN PROCEDURES - TOYOTA»(ref-158393) article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

Scheme 208

1. Disconnect electrical connector and vacuum hoses from Air Intake Control Valve (AICV) Vacuum Switching Valve (VSV). (Scheme 201), (Scheme 202) and (Scheme 209).
2. Using ohmmeter, check that continuity exists between electrical terminals on AICV VSV and that resistance is 37-44 ohms at 68°F (20°C). If continuity exists and resistance is within specification, go to next step. If no continuity exists or resistance is not within specification, replace AICV VSV.
3. Apply air pressure to port "E" on AICV VSV. Ensure air flows from the filter. (Scheme 210)
4. Apply battery voltage and ground to electrical terminals on AICV VSV. Apply air pressure to port "E" on AICV VSV. Ensure air flows from port "F". (Scheme 210) If AICV VSV operates properly, reinstall electrical connector and vacuum hoses on AICV VSV. Go to next step. If AICV VSV does not operate properly, replace AICV VSV.
5. For models produced up to January 2003, disconnect vacuum hose at actuator for air intake control valve. (Scheme 201), (Scheme 202) and (Scheme 209). Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator. Ensure actuator rod moves and does not return to original position for at least one minute. If actuator operates properly, reconnect vacuum hose. Go to next step. If actuator does not operate properly, replace actuator.
6. For models produced in January 2003 and later, disconnect vacuum hose from actuator valve No. 3, located on air cleaner case. Using vacuum pump, apply 7.9 in. Hg of vacuum to actuator valve. Ensure actuator valve opens and remains opened for at least one minute. If actuator valve operates properly, reconnect vacuum hose and go to next step. If actuator valve does not operate properly, replace actuator valve.
7. On all models, remove glove box for access to Engine Control Module (ECM). For illustration of ECM location, see «ENGINE CONTROL MODULE»(ref-151979-S42582171412003100300000) under COMPONENT LOCATIONS. Note ECM electrical connector terminal identification. (Scheme 256) Turn ignition on. Using voltmeter, check voltage between terminals No. 25 (on models produced before January 2003), or No. 33 (on models produced after January 2003), and No. 28 at ECM electrical connector E10. These are the AICV and E2 terminals at ECM.
8. Voltage should be 9-14 volts. If voltage is within specification, go to next step. If voltage is not within specification, check for open and short in wiring harness and connectors between EFI main relay, AICV VSV and ECM. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment and may also be referred to as EFI relay. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article.
9. Disconnect hoses from vacuum tank. Vacuum tank is located on upper cap on air cleaner assembly. (Scheme 201) Note ports on vacuum tank. (Scheme 207) Plug port "C" on vacuum tank. Apply air pressure to port "B". Ensure air flows from port "A".
10. Plug port "C". Apply air pressure to port "A". Ensure air does not flow from port "B". Plug ports "A" and "C". Using vacuum pump, apply 18 in. Hg of vacuum to port "B". Ensure vacuum reading will hold for at least one minute. If vacuum tank is okay, reconnect vacuum hoses and go to next step. If vacuum tank is defective, replace vacuum tank or upper cap on air cleaner assembly as necessary.
11. Check ECM ground circuit. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If ECM ground circuit is okay, replace ECM. If ECM is replaced and vehicle is equipped with engine immobilizer system, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see «COMPUTER RELEARN PROCEDURES - TOYOTA»(ref-158393) article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

Scheme 209

Scheme 210

CRANKING HOLD FUNCTION CIRCUIT

Land Cruiser

Note. Cranking Hold Function Circuit may be referred to as starter signal circuit.

For cranking hold function circuit inspection and wiring diagram (Scheme 211)- (Scheme 221). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 211

Scheme 212

Scheme 213

Scheme 214

Scheme 215

Scheme 216

Scheme 217

Scheme 218

Scheme 219

Scheme 220

Scheme 221

Sequoia & Tundra 4.7L

Note. Cranking Hold Function Circuit maybe referred to as starter signal circuit.

For cranking hold function circuit inspection and wiring diagram (Scheme 222)- (Scheme 233). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 222

Scheme 223

Scheme 224

Scheme 225

Scheme 226

Scheme 227

Scheme 228

Scheme 229

Scheme 230

Scheme 231

Scheme 232

Scheme 233

4Runner

Note. Cranking Hold Function Circuit maybe referred to as starter signal circuit.

For cranking hold function circuit inspection and wiring diagram (Scheme 234)- (Scheme 245). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 234

Scheme 235

Scheme 236

Scheme 237

Scheme 238

Scheme 239

Scheme 240

Scheme 241

Scheme 242

Scheme 243

Scheme 244

Scheme 245

ENGINE CONTROL MODULE POWER & GROUND CIRCUITS

For testing of Engine Control Module (ECM) power and ground circuits and identification of ECM electrical connector terminals, see ENGINE CONTROL MODULE POWER SOURCE CIRCUIT . Also see PIN VOLTAGE CHARTS article. For illustration of ECM location, see ENGINE CONTROL MODULE under COMPONENT LOCATIONS.

ENGINE CONTROL MODULE POWER SOURCE CIRCUIT

Note. When performing test for Engine Control Module (ECM) power source circuit, it may be necessary to check wiring harness and components connected to a specified fuse, or check wiring harness and electrical connectors between EFI main relay and battery. For additional wiring information for fuse and power supply circuit, see POWER DISTRIBUTION in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

Avalon

For engine control module power source circuit inspection (Scheme 246)- (Scheme 249). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Scheme 246

Scheme 247

Scheme 248

Scheme 249

Scheme 250

For engine control module power source circuit inspection (Scheme 251)- (Scheme 256). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Scheme 251

Scheme 252

Scheme 253

Scheme 254

Scheme 255

Scheme 256

For engine control module power source circuit inspection (Scheme 257)- (Scheme 261). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Scheme 257

Scheme 258

Scheme 259

Scheme 260

Scheme 261

For engine control module power source circuit inspection (Scheme 262)- (Scheme 265). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Scheme 262

Scheme 263

Scheme 264

Scheme 265

For engine control module power source circuit inspection (Scheme 266)- (Scheme 270). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Scheme 266

Scheme 267

Scheme 268

Scheme 269

Scheme 270

Sequoia

For engine control module power source circuit inspection (Scheme 271)- (Scheme 275). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Scheme 271

Scheme 272

Scheme 273

Scheme 274

Scheme 275

For engine control module power source circuit inspection (Scheme 276)- (Scheme 279). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

Scheme 276

Scheme 277

Scheme 278

Scheme 279

Tacoma

For engine control module power source circuit inspection (Scheme 280)- (Scheme 285). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Scheme 280

Scheme 281

Scheme 282

Scheme 283

Scheme 284

Scheme 285

Tundra 3.4L

For engine control module power source circuit inspection (Scheme 286)- (Scheme 290). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Scheme 286

Scheme 287

Scheme 288

Scheme 289

Scheme 290

Tundra 4.7L

For engine control module power source circuit inspection (Scheme 291)- (Scheme 295). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Scheme 291

Scheme 292

Scheme 293

Scheme 294

Scheme 295

For engine control module power source circuit inspection (Scheme 296)- (Scheme 302). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check EFI main relay, see EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Scheme 296

Scheme 297

Scheme 298

Scheme 299

Scheme 300

Scheme 301

Scheme 302

FUEL PUMP CONTROL CIRCUIT

For fuel pump control circuit inspection and wiring diagram (Scheme 303)- (Scheme 309). To check starter signal circuit, see STARTER SIGNAL CIRCUIT. To check ECM power source circuit, see ENGINE CONTROL MODULE POWER SOURCE CIRCUIT. To check circuit opening relay, see CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check fuel pump operation, see FUEL DELIVERY under FUEL SYSTEMS. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 303

Scheme 304

Scheme 305

Scheme 306

Scheme 307

Scheme 308

Scheme 309

For fuel pump control circuit inspection and wiring diagram (Scheme 310)- (Scheme 316). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 310

Scheme 311

Scheme 312

Scheme 313

Scheme 314

Scheme 315

Scheme 316

For fuel pump control circuit inspection and wiring diagram (Scheme 317)- (Scheme 322). To check starter signal circuit, see STARTER SIGNAL CIRCUIT. To check ECM power source circuit, see ENGINE CONTROL MODULE POWER SOURCE CIRCUIT. To check circuit opening relay, see CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check fuel pump operation, see FUEL DELIVERY under FUEL SYSTEMS. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 317

Scheme 318

Scheme 319

Scheme 320

Scheme 321

Scheme 322

For fuel pump control circuit inspection and wiring diagram (Scheme 323)- (Scheme 328). To check starter signal circuit, see STARTER SIGNAL CIRCUIT. To check ECM power source circuit, see ENGINE CONTROL MODULE POWER SOURCE CIRCUIT. To check circuit opening relay, see CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check fuel pump operation, see FUEL DELIVERY under FUEL SYSTEMS. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 323

Scheme 324

Scheme 325

Scheme 326

Scheme 327

Scheme 328

For fuel pump control circuit inspection and wiring diagram (Scheme 329)- (Scheme 335). To check fuel pump relay, see FUEL PUMP RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. To check fuel pump operation, see FUEL DELIVERY under FUEL SYSTEMS. To check circuit opening relay, see CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check fuel pump resistor operation, see FUEL DELIVERY under FUEL SYSTEMS.

Scheme 329

Scheme 330

Scheme 331

Scheme 332

Scheme 333

Scheme 334

Scheme 335

For fuel pump control circuit inspection and wiring diagram (Scheme 336)- (Scheme 342). To check fuel pump relay, see FUEL PUMP RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. To check fuel pump operation, see FUEL DELIVERY under FUEL SYSTEMS. To check circuit opening relay, see CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check fuel pump resistor operation, see FUEL DELIVERY under FUEL SYSTEMS.

Scheme 336

Scheme 337

Scheme 338

Scheme 339

Scheme 340

Scheme 341

Scheme 342

For fuel pump control circuit inspection and wiring diagram (Scheme 343)- (Scheme 346). To check starter signal circuit, see STARTER SIGNAL CIRCUIT. To check ECM power source circuit, see ENGINE CONTROL MODULE POWER SOURCE CIRCUIT. To check circuit opening relay, see CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check fuel pump operation, see FUEL DELIVERY under FUEL SYSTEMS. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 343

Scheme 344

Scheme 345

Scheme 346

For fuel pump control circuit inspection and wiring diagram (Scheme 347)- (Scheme 354). To check fuel pump operation, see FUEL DELIVERY under FUEL SYSTEMS. To check circuit opening relay, see CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 347

Scheme 348

Scheme 349

Scheme 350

Scheme 351

Scheme 352

Scheme 353

Scheme 354

For fuel pump control circuit inspection and wiring diagram (Scheme 347)and (Scheme 355) - (Scheme 360). To check starter signal circuit, see STARTER SIGNAL CIRCUIT. To check ECM power source circuit, see ENGINE CONTROL MODULE POWER SOURCE CIRCUIT. To check circuit opening relay, see CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check fuel pump operation, see FUEL DELIVERY under FUEL SYSTEMS. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 355

Scheme 356

Scheme 357

Scheme 358

Scheme 359

Scheme 360

Fuel pump control circuit test is not available from manufacturer. If problem exists in fuel pump control circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

For fuel pump control circuit description and inspection (Scheme 361)and (Scheme 363) - (Scheme 372). For fuel pump control circuit wiring diagram (Scheme 373) To check ECM power source circuit, see ENGINE CONTROL MODULE POWER SOURCE CIRCUIT. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

4Runner 4.7L

For fuel pump control circuit description and inspection (Scheme 362)and (Scheme 363) - (Scheme 372). For fuel pump control circuit wiring diagram (Scheme 374) To check ECM power source circuit, see ENGINE CONTROL MODULE POWER SOURCE CIRCUIT. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 361

Scheme 362

Scheme 363

Scheme 364

Scheme 365

Scheme 366

Scheme 367

Scheme 368

Scheme 369

Scheme 370

Scheme 371

Scheme 372

Scheme 373

Scheme 374

STARTER SIGNAL CIRCUIT

Note. Starter signal circuit is mainly used to increase fuel injection volume during engine starting. Starter signal circuit test is based on the premise that engine cranks normally. If engine will not crank, diagnose by symptom. See SYMPTOMS in TROUBLE SHOOTING - NO CODES article.

For starter signal circuit inspection and wiring diagram (Scheme 375)- (Scheme 378). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 375

Scheme 376

Scheme 377

Scheme 378

For starter signal circuit inspection and wiring diagram (Scheme 379)- (Scheme 384). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check park/neutral position switch, see PARK/NEUTRAL POSITION SWITCH under ENGINE SENSORS & SWITCHES. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL

Scheme 379

Scheme 380

Scheme 381

Scheme 382

Scheme 383

Scheme 384

For starter signal circuit inspection and wiring diagram (Scheme 379), (Scheme 384), (Scheme 385) - (Scheme 388). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 385

Scheme 386

Scheme 387

Scheme 388

For starter signal circuit inspection and wiring diagram (Scheme 389)- (Scheme 392). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 389

Scheme 390

Scheme 391

Scheme 392

For starter signal circuit inspection and wiring diagram (Scheme 393)- (Scheme 396). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 393

Scheme 394

Scheme 395

Scheme 396

For starter signal circuit inspection, see DTC P0617: STARTER RELAY CIRCUIT HIGH under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - LAND CRUISER.

For starter signal circuit inspection, see DTC P0617: STARTER RELAY CIRCUIT HIGH under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - SEQUOIA.

For starter signal circuit inspection and wiring diagram (Scheme 397)- (Scheme 400). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 397

Scheme 398

Scheme 399

Scheme 400

For starter signal circuit inspection and wiring diagram (Scheme 401)- (Scheme 406). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. To check park/neutral position switch, see PARK/NEUTRAL POSITION SWITCH under ENGINE SENSORS & SWITCHES.

Scheme 401

Scheme 402

Scheme 403

Scheme 404

Scheme 405

Scheme 406

For starter signal circuit inspection and wiring diagram (Scheme 407)- (Scheme 412). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check ignition switch, see appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. To check park/neutral position switch, see PARK/NEUTRAL POSITION SWITCH under ENGINE SENSORS & SWITCHES.

Scheme 407

Scheme 408

Scheme 409

Scheme 410

Scheme 411

Scheme 412

For starter signal circuit inspection, see DTC P0617: STARTER RELAY CIRCUIT HIGH under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - TUNDRA V8.

For starter signal circuit inspection, see appropriate SELF-DIAGNOSTICS - 4RUNNER article.

Camry, Land Cruiser, Sequoia, Tundra & 4Runner

Note. Accelerator pedal position sensor is also referred to as a throttle/pedal position sensor/switch.

For testing of accelerator pedal position sensor, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

All Vehicles (Except Tacoma)

1. Disconnect electrical connector for A/C compressor lock sensor and magnetic clutch on front of A/C compressor. This is the electrical located near front of A/C compressor.
2. Using ohmmeter, check resistance between terminals No. 1 and 2 on electrical connector for A/C compressor lock sensor and magnetic clutch. (Scheme 413)and (Scheme 414). Ensure resistance is within specification. See «A/C COMPRESSOR LOCK SENSOR RESISTANCE»(ref-151979-S33035423562003102200000) table. Replace A/C compressor lock sensor if resistance is within specification. It may be necessary to replace A/C compressor along with A/C compressor lock sensor as an assembly. Consult parts department for parts availability.

A/C COMPRESSOR LOCK SENSOR RESISTANCE

Scheme 413

Scheme 414

AIR/FUEL SENSOR

Note. Air/Fuel (A/F) sensor may also be referred to as Air/Fuel (A/F) ratio sensor.

Avalon, Camry Solara, Highlander & Sienna

1. Two heated A/F sensors are used, one on each exhaust manifold. Heated A/F sensor on rear (firewall side) exhaust manifold may also be referred to as bank No. 1 sensor No. 1. Heated A/F sensor on front (radiator side) exhaust manifold may also be referred to as bank No. 2 sensor No. 1.
2. If problem exists in A/F sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
3. To test heater resistance on A/F sensor, disconnect electrical connector at A/F sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 415)- (Scheme 417).
4. Replace A/F sensor if resistance is not.8-1.4 ohms at 68°F (20°C) and 1.8-3.2 ohms at 1472°F (800°C). See «AIR/FUEL SENSOR»(ref-151984-S16118696122003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.

Scheme 415

Scheme 416

1. Two heated A/F sensors are used, one on each exhaust manifold. Heated A/F sensor on rear (firewall side) exhaust manifold may also be referred to as bank No. 1 sensor No. 1. Heated A/F sensor on front (radiator side) exhaust manifold may also be referred to as bank No. 2 sensor No. 1.
2. If problem exists in A/F sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
3. To test heater resistance on A/F sensor, disconnect electrical connector at A/F sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 417) Replace A/F sensor if resistance is not 1.8-3.4 ohms at 68°F (20°C). See «AIR/FUEL SENSOR»(ref-151984-S16118696122003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
4. To check that heater is not shorted, using ohmmeter, check that no continuity exists between E1 and HT terminals on electrical connector. (Scheme 417) Replace A/F sensor if continuity exists. See «AIR/FUEL SENSOR»(ref-151984-S16118696122003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.

Scheme 417

Tacoma & Tundra 3.4L

1. Heated A/F sensor is located on exhaust pipe in front of catalytic converter. Heated A/F sensor may also be referred to as bank No. 1 sensor No. 1. If problem exists in A/F sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
2. To test heater resistance on A/F sensor, disconnect electrical connector at A/F sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 418) Replace A/F sensor if resistance is not.8-1.4 ohms at 68°F (20°C) and 1.8-3.2 ohms at 1472°F (800°C). «AIR/FUEL SENSOR»(ref-151984-S16118696122003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.

Scheme 418

1. Two heated A/F sensors are used, one on each exhaust manifold. Heated A/F sensor on passenger side exhaust manifold may be referred to as bank No. 1 sensor No. 1. Heated A/F sensor on driver side exhaust manifold may also be referred to as bank No. 2 sensor No. 1.
2. If problem exists in A/F sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
3. To test heater resistance on A/F sensor, disconnect electrical connector at A/F sensor. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 419) Replace A/F sensor if resistance is not 1.8-3.4 ohms at 68°F (20°C) and 5.0-7.5 ohms at 932°F (500°C). See «AIR/FUEL SENSOR»(ref-151984-S16118696122003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
4. To check that heater is not shorted, using ohmmeter, check that no continuity exists between AF- and HT terminals on electrical connector. (Scheme 419) Replace A/F sensor if continuity exists. See «AIR/FUEL SENSOR»(ref-151984-S16118696122003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.

Scheme 419

AIRFLOW METER

Note. Airflow meter may also be referred to as Mass Airflow (MAF) meter.

All Models

1. Remove airflow meter. See «AIRFLOW METER»(ref-151984-S24928640612003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
2. Note identification of terminals E2 and THA on airflow meter. (Scheme 420)- (Scheme 423). Using ohmmeter, check resistance between terminals E2 and THA on airflow meter. Resistance should be within specification in relation to the temperature. See «AIRFLOW METER RESISTANCE»(ref-151979-S12167457272003010900000) table. Replace airflow meter if resistance is not within specification.
3. Airflow meter operation should be checked. On Avalon, Camry Solara, Land Cruiser, Sequoia, Sienna, Tacoma, Tundra, and 4Runner 4.7L, go to next step. On Camry, Highlander and 4Runner 4.0L, go to step 6.
4. Install electrical connector on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 424)- (Scheme 427).
5. Turn ignition on. Apply air into designated area on airflow meter and note voltage reading. While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Turn ignition off. Remove voltmeter.
6. Apply battery voltage to +B terminal on airflow meter and battery ground to E2G terminal on airflow meter. Connect voltmeter leads to proper terminals on airflow meter. Apply air into designated area on airflow meter and note voltage reading. (Scheme 421) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Disconnect battery and remove voltmeter.

AIRFLOW METER RESISTANCE

Scheme 420

Scheme 421

Scheme 422

Scheme 423

Scheme 424

Scheme 425

Scheme 426

Scheme 427

BRAKELIGHT SWITCH

Note. Brakelight switch may also be referred to as stoplight switch.

Avalon, Sienna, Tacoma & Tundra

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of the brake pedal. Note terminal identification on brakelight switch. (Scheme 428)
2. On models without cruise control, using ohmmeter, check that no continuity exists between terminals No. 1 and 2 with brake pedal released so pin on brakelight switch is pushed in. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed so pin on brakelight switch is extended. Adjust or replace brakelight switch if operation is not as described.
3. On models with cruise control, using ohmmeter, check that no continuity exists between terminals No. 1 and 2 with brake pedal released so pin on brakelight switch is pushed in. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed so pin on brakelight switch is extended.
4. Check that no continuity exists between terminals No. 3 and 4 with brake pedal depressed so pin on brakelight switch is extended. Check that continuity exists between terminals No. 3 and 4 with brake pedal released so pin on brakelight switch is pushed in. Adjust or replace brakelight switch if operation is not as described. See «BRAKELIGHT SWITCH»(ref-151984-S36726850362003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.

Scheme 428

Camry, Camry Solara, Highlander & Land Cruiser

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on the brakelight switch. (Scheme 429)
2. Using ohmmeter, check that continuity exists between terminals No. 1 and 2 with brake pedal depressed so pin on brakelight switch is extended. Check that no continuity exists between terminals No. 1 and 2 with brake pedal released so pin on brakelight switch is pushed in.
3. Check that no continuity exists between terminals No. 3 and 4 with brake pedal depressed so pin on brakelight switch is extended. Check that continuity exists between terminals No. 3 and 4 with brake pedal released so pin on brakelight switch is pushed in. Adjust or replace brakelight switch if operation is not as described. See «BRAKELIGHT SWITCH»(ref-151984-S36726850362003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.

Scheme 429

1. Disconnect electrical connector for brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on electrical connector for brakelight switch. (Scheme 430)
2. Using ohmmeter, check that continuity exists between terminals No. 1 and 4 with brake pedal depressed so pin on brakelight switch is extended. Check that no continuity exists between terminals No. 1 and 4 with brake pedal released so pin on brakelight switch is pushed in.
3. Check that no continuity exists between terminals No. 2 and 3 with brake pedal depressed so pin on brakelight switch is extended. Check that continuity exists between terminals No. 2 and 3 with brake pedal released so pin on brakelight switch is pushed in. Adjust or replace brakelight switch if operation is not as described. See «BRAKELIGHT SWITCH»(ref-151984-S36726850362003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.

Scheme 430

1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of the brake pedal. Note terminal identification on brakelight switch. (Scheme 431)
2. Check that continuity exists between terminals No. 1 and 2 with brake pedal released so pin on brakelight switch is pushed in. Check that no continuity exists between terminals No. 1 and 2 with brake pedal depressed so pin on brakelight switch is extended.
3. Check that continuity exists between terminals No. 3 and 4 with brake pedal depressed so pin on brakelight switch is extended. Check that no continuity exists between terminals No. 3 and 4 with brake pedal released so pin on brakelight switch is pushed in. Adjust or replace brakelight switch if operation is not as described. See «BRAKELIGHT SWITCH»(ref-151984-S36726850362003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.

Scheme 431

CAMSHAFT POSITION SENSOR

For testing camshaft position sensor, see CAMSHAFT POSITION SENSOR under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

CRANKSHAFT POSITION SENSOR

For testing crankshaft position sensor, see CRANKSHAFT POSITION SENSOR under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

Camry & Camry Solara

Note. Applies for Camry models produced up to January 2003.

1. Remove EGR gas temperature sensor. EGR gas temperature sensor is screwed into bottom of pipe that EGR valve is mounted on. It may be necessary to remove throttle body for access to EGR gas temperature sensor. If necessary to remove throttle body for access to EGR gas temperature sensor, see «THROTTLE BODY»(ref-151984-S20444146202003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article.
2. Place threaded end of EGR gas temperature sensor and thermometer in container of oil. Attach ohmmeter between electrical terminals on EGR gas temperature sensor.
3. Heat oil and note resistance at specified temperature. See «EGR GAS TEMPERATURE SENSOR RESISTANCE»(ref-151979-S12324667612003010900000) table. Replace EGR gas temperature sensor if resistance is not within specification. Reinstall EGR gas temperature sensor.

EGR GAS TEMPERATURE SENSOR RESISTANCE

Note. Applies for Camry models produced up to January 2003.

For testing of EGR position sensor, see EGR POSITION SENSOR (CAMRY & CAMRY SOLARA) under EMISSION SYSTEMS & SUB-SYSTEMS.

1. Ensure ignition is off. Note location of Engine Coolant Temperature (ECT) sensor. See «ENGINE COOLANT TEMPERATURE SENSOR LOCATION»(ref-151979-S04489927602003010900000) table. Remove ECT sensor. See «ENGINE COOLANT TEMPERATURE SENSOR»(ref-151984-S40345071782003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
2. Place probe end of ECT sensor and thermometer in container of water. Attach ohmmeter between electrical terminals on ECT sensor. Heat water and note that resistance is within specification in relation to temperature. (Scheme 432) Replace ECT sensor if resistance is not within specification.

ENGINE COOLANT TEMPERATURE SENSOR LOCATION

Scheme 432

1. A heated Air/Fuel (A/F) sensor is used on each exhaust manifold and heated oxygen sensor is used on exhaust pipe behind catalytic converter. For testing of A/F sensor, see «AIR/FUEL SENSOR»(ref-151979-S02109168032003102200000). Heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector for heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 433) Electrical connector for heated oxygen sensor is located below passenger's side front seat, near center console and contains a Dark Gray 4-pin electrical connector.
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 433) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
4. If problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 433

1. A heated Air/Fuel (A/F) sensor is used on each exhaust manifold and a heated oxygen sensor is used on exhaust pipe behind catalytic converter. For testing of A/F sensor, see «AIR/FUEL SENSOR»(ref-151979-S02109168032003102200000). Heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector for heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 434)and (Scheme 435).
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 434)and (Scheme 435). Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
4. To check that heater is not shorted, using ohmmeter, check that no continuity exists between E1 and HT terminals on electrical connector. (Scheme 434)and (Scheme 435). Replace heated oxygen sensor if continuity exists. See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
5. If problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 434

Scheme 435

1. A heated Air/Fuel (A/F) sensor is used on each exhaust manifold and a heated oxygen sensor is used on exhaust pipe behind catalytic converter. For testing of A/F sensor, see «AIR/FUEL SENSOR»(ref-151979-S02109168032003102200000). Heated oxygen sensor on the exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector at appropriate heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 436) Electrical connector for heated oxygen sensor on exhaust pipe behind catalytic converter is located below driver's side front seat, below carpet near center console and contains a Dark Gray 4-pin electrical connector.
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 436) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
4. If problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 436

1. A heated Air/Fuel (A/F) sensor is used on each exhaust manifold and a heated oxygen sensor is used on exhaust pipe behind catalytic converter. For testing of A/F sensor, see «AIR/FUEL SENSOR»(ref-151979-S02109168032003102200000). Heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector for heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 437)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C) and 1.8-3.2 ohms at 472°F (800°C). See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
4. If problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 437

Land Cruiser, Sequoia, Tundra 4.7L & 4Runner 4.7L

1. Four heated oxygen sensors are used, one on each exhaust manifold and one on each exhaust pipe behind catalytic converter. On driver's side, heated oxygen sensor on exhaust manifold may also be referred to as bank No. 1 sensor No. 1 and heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2. On passenger's side, heated oxygen sensor on exhaust manifold may also be referred to as bank No. 2 sensor No. 1 and heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 2 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector at appropriate heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 438)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 438) On Land Cruiser, Sequoia and 4Runner 4.7L, resistance should be 11-16 ohms at 68°F (20°C). On Tundra 4.7L, resistance should be 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). On all models, replace heated oxygen sensor if resistance is not within specification. See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
4. On 4Runner 4.7L, to check that heater is not shorted, using ohmmeter, check that no continuity exists between E1 and HT terminals on electrical connector. (Scheme 441) Replace heated oxygen sensor if continuity exists. See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
5. On all models, if a problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 438

1. A heated Air/Fuel (A/F) sensor is used on each exhaust manifold and a heated oxygen sensor is used on exhaust pipe behind catalytic converter. For testing of A/F sensor, see «AIR/FUEL SENSOR»(ref-151979-S02109168032003102200000). Heated oxygen sensor on exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector at heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 439) Electrical connector for heated oxygen sensor is located below passenger's side front seat, underneath the carpet and contains a Dark Gray 4-pin electrical connector.
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 439) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
4. If problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 439

1. A heated Air/Fuel (A/F) sensor is used on exhaust pipe in front of catalytic converter and a heated oxygen sensor is used on exhaust pipe behind catalytic converter. For testing of A/F sensor, see «AIR/FUEL SENSOR»(ref-151979-S02109168032003102200000). Heated oxygen sensor exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector at heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 440)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 440) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472°F (800°C). See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
4. If problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 440

1. A heated Air/Fuel (A/F) sensor is used on each exhaust pipe in front of catalytic converter and a heated oxygen sensor is used on each exhaust pipe behind catalytic converter. For testing of A/F sensors, see «AIR/FUEL SENSOR»(ref-151979-S02109168032003102200000). Heated oxygen sensor on passenger side exhaust pipe behind catalytic converter may also be referred to as bank No. 1 sensor No. 2. Heated oxygen sensor on driver side exhaust pipe behind catalytic converter may also be referred to as bank No. 2 sensor No. 2.
2. To test heater on heated oxygen sensor, disconnect electrical connector at appropriate heated oxygen sensor and note heated oxygen sensor terminals. (Scheme 441)
3. Using ohmmeter, check resistance between +B and HT terminals on electrical connector. (Scheme 441) Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C). See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
4. To check that heater is not shorted, using ohmmeter, check that no continuity exists between E1 and HT terminals on electrical connector. (Scheme 441) Replace heated oxygen sensor if continuity exists. See «HEATED OXYGEN SENSOR»(ref-151984-S41146403752003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
5. If problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Scheme 441

1. Disconnect electrical connector from ignition switch on bottom of upper steering column bracket. (Scheme 442) Note ignition switch electrical terminals and ignition lock cylinder positions. (Scheme 443)- (Scheme 446).
2. Using ohmmeter, check that continuity is as specified between indicated ignition switch electrical terminals in relation to ignition lock cylinder position. See «IGNITION SWITCH CONTINUITY»(ref-151979-S15843110322003010900000) table. Replace ignition switch if defective. See «IGNITION SWITCH»(ref-151984-S10931634082003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.

IGNITION SWITCH CONTINUITY

Scheme 442

Scheme 443

Scheme 444

Scheme 445

Scheme 446

Intake air temperature sensor is incorporated with airflow meter. See AIRFLOW METER .

Avalon, Camry, Camry Solara, Highlander, Sienna, Tacoma & Tundra 3.4L

1. Knock sensors No. 1 and 2 are located below intake manifold on cylinder block. (Scheme 447)and (Scheme 448). Manufacturer recommends removing knock sensor from cylinder block before testing. See «KNOCK SENSOR»(ref-151984-S34686470832003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
2. Using ohmmeter, check that no continuity exists between electrical terminal on knock sensor and body of knock sensor. Replace knock sensor if continuity exists.

Scheme 447

Scheme 448

1. Knock sensors No. 1 and 2 are located below intake manifold on cylinder block. (Scheme 449) Remove intake manifolds for access to knock sensor. See «KNOCK SENSOR»(ref-151984-S34686470832003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article for removal of intake manifolds.
2. Disconnect electrical connector at knock sensor. Using ohmmeter, check that no continuity exists between electrical terminal on knock sensor and body of knock sensor. Replace knock sensor if continuity exists.

Scheme 449

1. Knock sensors No. 1 and 2 are located below intake manifold on cylinder block. (Scheme 450) Manufacturer recommends removing knock sensor from cylinder block before testing. See «KNOCK SENSOR»(ref-151984-S34686470832003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8.
2. Using an ohmmeter, measure the resistance between the knock sensor terminals. Resistance should be 120-280 k/ohms at 68°F (20°C). (Scheme 451) If the resistance is not as specified, replace the knock sensor. See «KNOCK SENSOR»(ref-151984-S34686470832003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8.

Scheme 450

Scheme 451

A/T Models

1. Disconnect electrical connector at Park/Neutral Position (PNP) switch. PNP switch is mounted on side of transmission/transaxle. Note terminal identification. (Scheme 452)- (Scheme 456).
2. Using ohmmeter, check for continuity between specified terminals with shift lever in proper positions. See «PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS»(ref-151979-S25389995682003010900000) table. If proper continuity does not exist, adjust or replace PNP switch as necessary. For adjustment or replacement of PNP switch, see «PARK/NEUTRAL POSITION SWITCH»(ref-151984-S37516839162003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.

PARK/NEUTRAL POSITION SWITCH SPECIFICATIONS

Scheme 452

Scheme 453

Scheme 454

Scheme 455

Scheme 456

Avalon, Camry, Camry Solara, Sienna, Tacoma, Tundra 3.4L & 4Runner 4.0L

Power steering pressure switch is located on power steering pump, near pressure hose. Testing information is not available from manufacturer.

For power steering pressure sensor inspection procedures (Scheme 457) To check ECM terminal locations, see PIN VOLTAGE CHARTS.

Scheme 457

For throttle position sensor circuit inspection and wiring diagram (Scheme 458)- (Scheme 461). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. To replace throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 458

Scheme 459

Scheme 460

Scheme 461

Camry (Up To January 2003 Production)

For throttle position sensor circuit inspection and wiring diagram (Scheme 462)- (Scheme 464). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To replace throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 462

Scheme 463

Scheme 464

Camry (January 2003 & Later Production)

For throttle position sensor circuit inspection and wiring diagram (Scheme 465)- (Scheme 469). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To replace throttle body, see THROTTLE BODY under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 465

Scheme 466

Scheme 467

Scheme 468

Scheme 469

For throttle position sensor circuit inspection and wiring diagram (Scheme 470)- (Scheme 473). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. To replace throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 470

Scheme 471

Scheme 472

Scheme 473

For throttle position sensor circuit inspection and wiring diagram (Scheme 474)- (Scheme 476). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. To replace throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 474

Scheme 475

Scheme 476

For throttle position sensor circuit inspection and wiring diagram (Scheme 477)- (Scheme 483). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To replace throttle control motor and sensor, see THROTTLE CONTROL MOTOR under MOTORS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 477

Scheme 478

Scheme 479

Scheme 480

Scheme 481

Scheme 482

Scheme 483

For throttle position sensor circuit inspection and wiring diagram (Scheme 484)- (Scheme 490). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To replace throttle control motor and sensor, see THROTTLE CONTROL MOTOR under MOTORS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 484

Scheme 485

Scheme 486

Scheme 487

Scheme 488

Scheme 489

Scheme 490

For throttle position sensor circuit inspection and wiring diagram (Scheme 491)- (Scheme 495). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. To replace throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 491

Scheme 492

Scheme 493

Scheme 494

Scheme 495

Tacoma (With ETCS)

For throttle position sensor circuit inspection and wiring diagram (Scheme 496)- (Scheme 501). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check throttle position sensor, see THROTTLE BODY under IDLE CONTROL SYSTEMS. To replace throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 496

Scheme 497

Scheme 498

Scheme 499

Scheme 500

Scheme 501

Tacoma (Without ETCS)

For throttle position sensor circuit inspection and wiring diagram (Scheme 502)- (Scheme 505). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. To check for intermittent problems, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. To replace throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 502

Scheme 503

Scheme 504

Scheme 505

For throttle position sensor circuit inspection and wiring diagram (Scheme 506)- (Scheme 511). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check throttle position sensor, see THROTTLE BODY under IDLE CONTROL SYSTEMS. To replace throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8.

Scheme 506

Scheme 507

Scheme 508

Scheme 509

Scheme 510

Scheme 511

For throttle position sensor circuit inspection and wiring diagram (Scheme 512)- (Scheme 518). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To replace throttle body, see THROTTLE CONTROL MOTOR under MOTORS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 512

Scheme 513

Scheme 514

Scheme 515

Scheme 516

Scheme 517

Scheme 518

For throttle position sensor circuit inspection and wiring diagram (Scheme 519)- (Scheme 523). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To replace throttle body, see THROTTLE CONTROL MOTOR under MOTORS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 519

Scheme 520

Scheme 521

Scheme 522

Scheme 523

For throttle position sensor circuit inspection and wiring diagram (Scheme 524)- (Scheme 528). For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To replace throttle body, see THROTTLE CONTROL MOTOR under MOTORS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 524

Scheme 525

Scheme 526

Scheme 527

Scheme 528

VAPOR PRESSURE SENSOR

For testing of vapor pressure sensor, see VAPOR PRESSURE SENSOR under FUEL EVAPORATIVE SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS.

Avalon, Camry, Highlander, Sienna & 4Runner 4.0L

Note. Procedure applies to January 2003 and later production Camry.

Variable Valve Timing (VVT) sensor may also be referred to as camshaft position sensor. For testing of VVT sensor, see CAMSHAFT POSITION SENSOR under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

1. Wheel speed sensors on each wheel deliver an input signal to Anti-Lock Brake System (ABS) Electronic Control Unit (ECU). ABS ECU converts input signals from wheel speed sensors to a 4-pulse input signal to the instrument cluster.
2. Instrument cluster then converts 4-pulse input signal to a rectangular waveform and then sends vehicle speed signal to Engine Control Module (ECM).
3. If problem exists with vehicle speed signal, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

For testing procedures of Vehicle Speed Sensor (VSS) (Scheme 529)- (Scheme 531).

Scheme 529

Scheme 530

Scheme 531

For testing procedures of Vehicle Speed Sensor (VSS) (Scheme 532)

Scheme 532

1. Wheel speed sensors on each wheel deliver an input signal to skid control Electronic Control Unit (ECU). Skid control ECU converts input signals from wheel speed sensors to a 4-pulse input signal to the instrument cluster.
2. Instrument cluster then converts 4-pulse input signal to a rectangular waveform and then sends vehicle speed signal to Engine Control Module (ECM).
3. If problem exists with vehicle speed signal, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

For testing procedures of Vehicle Speed Sensor (VSS) see scheme 366

For testing procedures of Vehicle Speed Sensor (VSS) see scheme 366

1. Wheel speed sensors on each wheel deliver an input signal to Anti-Lock Brake System (ABS) Electronic Control Unit (ECU). ABS ECU converts input signals from wheel speed sensors to a 4-pulse input signal to the instrument cluster.
2. Instrument cluster then converts 4-pulse input signal to a rectangular waveform and then sends vehicle speed signal to Engine Control Module (ECM).
3. If problem exists with vehicle speed signal, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

For testing Vehicle Speed Sensor (VSS) (Scheme 533)

Scheme 533

Tundra

For testing procedures of Vehicle Speed Sensor (VSS) see scheme 366

1. Wheel speed sensors on each wheel deliver an input signal to Vehicle Skid Control (VSC) Electronic Control Unit (ECU). VSC ECU converts input signals from wheel speed sensors to a 4-pulse input signal to the instrument cluster.
2. Instrument cluster then converts 4-pulse input signal to a rectangular waveform and then sends vehicle speed signal to Engine Control Module (ECM).
3. If problem exists with vehicle speed signal, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Camry, Land Cruiser, Sequoia, Tacoma With ETCS, Tundra & 4Runner 4.7L

For testing of throttle control motor, see THROTTLE BODY under IDLE CONTROL SYSTEMS.

A/F HEATER RELAY

Note. A/F heater relay may also be referred to as A/F HTR relay, A/F sensor relay or A/F relay.

Avalon, Camry, Camry Solara, Highlander, Sienna & 4Runner 4.0L

1. Remove A/F heater relay. See «A/F HEATER RELAY LOCATION»(ref-151979-S29450392732003010900000) table.
2. To test A/F heater relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on A/F heater relay. (Scheme 534)and (Scheme 535).
3. To test A/F heater relay operation, apply battery voltage and ground to A/F heater relay and use ohmmeter to check for continuity between specified terminals on A/F heater relay. (Scheme 534)and (Scheme 535). Replace A/F heater relay if defective.

A/F HEATER RELAY LOCATION

Scheme 534

Scheme 535

Scheme 536

1. Ensure ignition is off. Remove circuit opening relay. See «CIRCUIT OPENING RELAY LOCATION»(ref-151979-S23014168792003010900000) table. (Scheme 537)- (Scheme 547).
2. To test circuit opening relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on circuit opening relay. see scheme 382and (Scheme 548).
3. To test circuit opening relay operation, apply battery voltage and ground to circuit opening relay and use ohmmeter to check for continuity between specified terminals on circuit opening relay. see scheme 382and (Scheme 548). Replace circuit opening relay if defective.

CIRCUIT OPENING RELAY LOCATION (1)

Scheme 537

Scheme 538

Scheme 539

Scheme 540

Scheme 541

Scheme 542

Scheme 543

Scheme 544

Scheme 545

Scheme 546

Scheme 547

Scheme 548

EFI MAIN RELAY

Note. EFI main relay may also be referred to as EFI relay.

1. Ensure ignition is off. Remove EFI main relay from fuse/relay box at driver's side front corner of engine compartment.
2. To test EFI main relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on EFI main relay. see scheme 382- (Scheme 549).
3. To test EFI main relay operation, apply battery voltage and ground to EFI main relay and use ohmmeter to check for continuity between specified terminals on EFI main relay. see scheme 382- (Scheme 549). Replace EFI main relay if defective.

Scheme 549

Land Cruiser, Sequoia, Tundra 4.7L & 4Runner

1. Ensure ignition is off. Remove fuel pump relay from fuse/relay box at driver's side front corner of engine compartment. (Scheme 541), (Scheme 542), (Scheme 546) and (Scheme 547)
2. To test fuel pump relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on fuel pump relay. (Scheme 550)and (Scheme 551).
3. To test fuel pump relay operation, apply battery voltage and ground to fuel pump relay and use ohmmeter to check for continuity between specified terminals on fuel pump relay. (Scheme 550)and (Scheme 551). Replace fuel pump relay if defective.

Scheme 550

Scheme 551

IG2 RELAY

Note. IG2 relay may also be referred to as ignition relay.

1. Ensure ignition is off. Remove IG2 relay from fuse/relay box at driver's side front corner of engine compartment.
2. To test IG2 relay continuity, using ohmmeter, check for continuity and no continuity between specified terminals on IG2 relay. see scheme 387
3. To test IG2 relay operation, apply battery voltage and ground to IG2 relay and use ohmmeter to check for continuity between specified terminals on IG2 relay. see scheme 387 Replace IG2 relay if defective.

FUEL SYSTEM PRESSURE RELEASE

For fuel system pressure release procedures, see FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article.

FUEL DELIVERY

Note. For fuel system pressure testing, see FUEL PRESSURE under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

Circuit Opening Relay

See CIRCUIT OPENING RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

See EFI MAIN RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Fuel Pump Relay (Land Cruiser, Sequoia, Tundra 4.7L & 4Runner)

See FUEL PUMP RELAY under MODULES, MOTORS, RELAYS & SOLENOIDS.

Fuel Pump Resistor (Land Cruiser, Sequoia, Tundra 4.7L & 4Runner)

1. On Land Cruiser, fuel pump resistor is located on passenger side of engine compartment. (Scheme 552) On Sequoia and Tundra, fuel pump resistor is located at driver's side front corner of engine compartment, near end of fuse/relay box. (Scheme 553) On 4Runner, fuel pump resistor is located at driver's side front corner of engine compartment, near center of fuse/relay box. Manufacturer lists testing procedure with fuel pump resistor removed. Disconnect electrical connector at fuel pump resistor.
2. Remove bolt and fuel pump resistor. Using ohmmeter, check resistance between electrical terminals on fuel pump resistor. Replace fuel pump resistor if resistance is not.70-.76 ohms at 68°F (20°C). Reinstall fuel pump resistor.

Scheme 552

Scheme 553

Fuel Injectors (Avalon)

For fuel injector testing procedures (Scheme 554)and (Scheme 555).

Scheme 554

Scheme 555

Fuel Injectors (Camry - Up To Jan. 2003 Production)

For fuel injector testing procedures (Scheme 556)and (Scheme 557).

Scheme 556

Scheme 557

Fuel Injectors (Camry - Jan. 2003 & Later Production)

For fuel injector testing procedures (Scheme 558)and (Scheme 559).

Scheme 558

Scheme 559

Fuel Injectors (Camry Solara)

For fuel injector testing procedures (Scheme 560)and (Scheme 561).

Scheme 560

Scheme 561

Fuel Injectors (Highlander)

For fuel injector testing procedures (Scheme 562)and (Scheme 563).

Scheme 562

Scheme 563

Fuel Injectors (Land Cruiser)

For fuel injector testing procedures (Scheme 564)- (Scheme 566).

Scheme 564

Scheme 565

Scheme 566

Fuel Injectors (Sequoia)

For fuel injector testing procedures (Scheme 567)and (Scheme 568).

Scheme 567

Scheme 568

Fuel Injectors (Sienna)

For fuel injector testing procedures (Scheme 569)and (Scheme 570).

Scheme 569

Scheme 570

Fuel Injectors (Tacoma)

For fuel injector testing procedures (Scheme 571)and (Scheme 572).

Scheme 571

Scheme 572

Fuel Injectors (Tundra 3.4L)

For fuel injector testing procedures (Scheme 573)and (Scheme 574).

Scheme 573

Scheme 574

Fuel Injectors (Tundra 4.7L)

For fuel injector testing procedures (Scheme 575)and (Scheme 576).

Scheme 575

Scheme 576

Fuel Injectors (4Runner 4.0L)

For fuel injector testing procedures (Scheme 577)and (Scheme 578).

Scheme 577

Scheme 578

Fuel Injectors (4Runner 4.7L)

For fuel injector testing procedures (Scheme 579)and (Scheme 580).

Scheme 579

Scheme 580

Fuel Cut System (Avalon, Camry Solara, Land Cruiser, Sequoia, Sienna, Tacoma, Tundra & 4Runner 4.0L)

1. On Avalon, Camry Solara and Sienna, remove "V" bank cover on top of engine for access to fuel injectors. (Scheme 200)and (Scheme 203).
2. On all models, connect Toyota hand-held tester or scan tool to data link connector No. 3 at driver's side of instrument panel. (Scheme 221), (Scheme 233), (Scheme 245), (Scheme 378), (Scheme 392), (Scheme 400), (Scheme 406) or (Scheme 412). Hand-held tester or scan tool is used to read engine RPM. Start engine. Warm engine to normal operating temperature.
3. Ensure A/C is off. Gradually increase engine speed to specified RPM. See «FUEL CUT SYSTEM TESTING SPEED»(ref-151979-S25843748722003010900000) table.
4. Using stethoscope, check for fuel injector operating sound. Ensure when throttle lever is released, fuel injector stops operating momentarily and then resumes operating (fuel return RPM).
5. Ensure fuel return RPM is within specification. See «FUEL CUT SYSTEM SPECIFICATIONS»(ref-151979-S11030733892003010900000) table. Shut engine off. Remove hand-held tester or scan tool.

FUEL CUT SYSTEM TESTING SPEED

FUEL CUT SYSTEM SPECIFICATIONS (1)

Fuel Cut System (Camry & Highlander)

1. Remove "V" bank cover on top of engine for access to fuel injectors. (Scheme 201)and (Scheme 204).
2. Connect Toyota hand-held tester or scan tool to data link connector No. 3 at driver's side of instrument panel. (Scheme 384)and (Scheme 396). Hand-held tester or scan tool is used to read engine RPM. Start engine. Warm engine to normal operating temperature.
3. Gradually increase engine speed to 3500 RPM. Using stethoscope, check for fuel injector operating sound. Ensure when throttle lever is released, fuel injector stops operating momentarily and then resumes operating. Shut engine off. Remove hand-held tester or scan tool.

1. Start engine. Warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-151949-S04785361952003010900000) in ON-VEHICLE ADJUSTMENTS - V6 & V8 article. Turn ignition off. Apply parking brake and place transaxle in Neutral. Ensure A/C is off.
2. On Avalon, install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on data link connector No. 1 located in the engine compartment on end of air intake chamber at passenger's side of engine. (Scheme 581) On Sienna, install Jumper Wire (SST 09843-18020) between terminals TC and E1 on data link connector No. 1 located on engine mount bracket at passenger's side front of engine. (Scheme 582)
3. On all models, start engine and note engine speed. Engine speed should increase to 1000 RPM for 5 seconds and then return to idle speed. If engine speed is as specified, turn ignition off and remove jumper wire. If engine speed is not as specified, turn ignition off, remove jumper wire and go to next step.
4. To test IAC valve operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-151984-S20444146202003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article. Check that valve on inside of IAC valve is half open. (Scheme 583) Reinstall electrical connector on IAC valve.
5. Turn ignition on. Check that valve on inside of IAC valve moves from half open to fully closed, fully open and then returns to half open within.5 seconds.
6. If IAC valve operates as specified, wiring circuit, Engine Control Module (ECM) and IAC valve are okay. If IAC valve operates properly but idle problem still exists, the air assist system may be defective. For testing of air assist system, see «AIR ASSIST SYSTEM»(ref-151979-S09373015312003010900000). If IAC valve does not operate, check wiring circuit between ECM and IAC valve. For Avalon, ECM is located behind glove box, near passenger's side kick panel. For Sienna, ECM is located on passenger's side of instrument panel, just below glove box. For illustration of ECM location (Scheme 181)and (Scheme 187). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL article. If wiring circuit and ECM are okay, replace IAC valve.

Scheme 581

Scheme 582

Scheme 583

For Idle Air Control (IAC) system testing procedures (Scheme 584)- (Scheme 586). To check air induction system, see ACOUSTIC CONTROL INDUCTION SYSTEM in AIR INDUCTION SYSTEMS. To replace air induction system, see AIR INDUCTION SYSTEMS in REMOVAL & INSTALLATION - V6 & V8. To replace throttle body, see THROTTLE BODY under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS. To check throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8.

Scheme 584

Scheme 585

Scheme 586

1. Start engine. Warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-151949-S04785361952003010900000) in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
2. Turn ignition off. Apply parking brake and place transmission/transaxle in Neutral. Ensure A/C is off.
3. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on data link connector No. 1 located at passenger's side of engine compartment, near strut tower. (Scheme 587)
4. Start engine and note engine speed. Engine speed should increase to 1000 RPM for 5 seconds and then return to idle speed. If engine speed is not as specified, test IAC valve resistance and IAC valve operation. Go to next step. If engine speed is as specified, remove jumper wire. Turn ignition off.
5. To test IAC valve resistance, ensure ignition is off. Disconnect electrical connector at IAC valve. IAC valve is located on lower area of throttle body. Using ohmmeter, checking resistance between +B terminal and each remaining terminal on IAC valve. (Scheme 588)
6. Replace IAC valve if resistance is not within specification. See «IAC VALVE RESISTANCE»(ref-151979-S41702743052003103100000) table.
7. To test IAC valve operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-151984-S20444146202003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article. Apply battery voltage to +B terminal on IAC valve. Apply battery ground to proper terminal and ensure valve opens and closes. (Scheme 589) Replace IAC valve if defective.
8. If IAC valve resistance is within specification and operates properly, check wiring circuit between Engine Control Module (ECM) and IAC valve. For illustration of ECM location (Scheme 183) For wiring diagram, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If all components and wiring circuit are okay, but idle problem still exists, the air assist system may be defective. For testing of air assist system, see «AIR ASSIST SYSTEM»(ref-151979-S09373015312003010900000).

IAC VALVE RESISTANCE

Scheme 587

Scheme 588

Scheme 589

1. If problem exists in Idle Air Control (IAC) valve or wiring circuit, a Diagnostic Trouble Code (DTC) P0505 may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
2. To test IAC operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-133227-S01273866582002021900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article. Reinstall electrical connector on IAC valve.
3. Turn ignition on. Check that valve on inside of IAC valve moves from half open to fully closed, fully open and then returns to half open within.5 seconds. (Scheme 583)
4. If IAC valve operates as specified, wiring circuit, Engine Control Module (ECM) and IAC valve are okay. Clear any stored DTCs from ECM after checking IAC valve operation. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article. If IAC valve does not operate, check wiring circuit between ECM and IAC valve. ECM is located behind glove box. For illustration of ECM location (Scheme 184) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL article. If wiring circuit and ECM are okay, replace IAC valve.

Land Cruiser & Sequoia

For Idle Air Control (IAC) system testing procedures (Scheme 590)and (Scheme 591). To check air induction system, see ACOUSTIC CONTROL INDUCTION SYSTEM in AIR INDUCTION SYSTEMS. To replace air induction system, see AIR INDUCTION SYSTEMS in REMOVAL & INSTALLATION - V6 & V8. To check throttle control system, see THROTTLE BODY. To replace throttle body, see THROTTLE BODY under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8. For circuit identification, see ENGINE PERFORMANCE in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 590

Scheme 591

Tacoma With ETCS & Tundra

For Idle Air Control (IAC) system testing procedures (Scheme 592)and (Scheme 591). To check air induction system, see ACOUSTIC CONTROL INDUCTION SYSTEM in AIR INDUCTION SYSTEMS. To replace air induction system, see AIR INDUCTION SYSTEMS in REMOVAL & INSTALLATION - V6 & V8. To check throttle control system, see THROTTLE BODY.

Scheme 592

Scheme 593

Tacoma Without ETCS

1. Start engine. Warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-151949-S04785361952003010900000) in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
2. Turn ignition off. Apply parking brake and place transmission/transaxle in Neutral. Ensure A/C is off.
3. Note location of data link connector No. 3 at driver's side of instrument panel. (Scheme 406) Install Jumper Wire (SST 09843-18040) between terminals No. 4 (CG) and 13 (TC) on data link connector No. 3. (Scheme 594) Go to next step.
4. Start engine and note engine speed. Engine speed should increase to 1000 RPM for 5 seconds and then return to idle speed. If engine speed is not as specified, test IAC valve resistance and IAC valve operation. Go to next step. If engine speed is as specified, remove jumper wire. Turn ignition off.
5. To test IAC valve resistance, ensure ignition is off. Disconnect electrical connector at IAC valve. IAC valve is located on lower area of throttle body. Using ohmmeter, checking resistance between +B terminal and each remaining terminal on IAC valve. (Scheme 595)
6. Replace IAC valve if resistance is not within specification. See «IAC VALVE RESISTANCE»(ref-151979-S31679338312003010900000) table.
7. To test IAC valve operation, remove IAC valve from throttle body. See «THROTTLE BODY»(ref-151984-S20444146202003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article. Apply battery voltage to +B terminal on IAC valve. Apply battery ground to proper terminal and ensure valve opens and closes. (Scheme 596) Replace IAC valve if defective.
8. If IAC valve resistance is within specification and operates properly, check wiring circuit between Engine Control Module (ECM) and IAC valve. For illustration of ECM location (Scheme 188) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If all components and wiring circuit are okay, but idle problem still exists, the air assist system may be defective. For testing of air assist system, see «AIR ASSIST SYSTEM»(ref-151979-S09373015312003010900000).

IAC VALVE RESISTANCE

Scheme 594

Scheme 595

Scheme 596

For Idle Air Control (IAC) system testing procedures (Scheme 597)(Scheme 592) and (Scheme 598) (Scheme 591). To check air induction system, see ACOUSTIC CONTROL INDUCTION SYSTEM in AIR INDUCTION SYSTEMS. To replace air induction system, see AIR INDUCTION SYSTEMS in REMOVAL & INSTALLATION - V6 & V8. To check throttle control system, see THROTTLE BODY.

Scheme 597

Scheme 598

1. Start engine. Warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-133194-S24824673952002021900000) in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
2. Turn ignition off. Apply parking brake and place transmission/transaxle in Neutral. Ensure A/C is off.
3. On Avalon, install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on data link connector No. 1 located in the engine compartment on end of air intake chamber at passenger's side of engine. (Scheme 581) On Sienna, install Jumper Wire (SST 09843-18020) between terminals TC and E1 on data link connector No. 1 located on engine mount bracket at passenger's side front of engine. (Scheme 582) Go to next step.
4. Start engine and note engine speed. After engine speed is kept at 900-1300 RPM for 10 seconds, ensure engine returns to idle speed. Turn ignition off.
5. Remove "V" bank cover located on top of engine (if necessary) and disconnect air assist hose from air pipe. (Scheme 599) Air assist hose fits between IAC valve and air pipe. Place plug on end of air pipe and air assist hose. Go to next step.
6. Start engine and note idle speed. Idle speed should be 500 RPM or less which may cause the engine to stall. Turn ignition off. If idle speed is not 500 RPM or less, check for air leak between air assist hoses, air pipe and fuel injectors. Remove plugs and jumper wire. Reconnect air assist hose.

Scheme 599

1. Start engine. Warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-133194-S24824673952002021900000) in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
2. Turn ignition off. Apply parking brake and place transmission/transaxle in Neutral. Ensure A/C is off.
3. Install Jumper Wire (SST 09843-18020) between terminals TE1 and E1 on data link connector No. 1 located at passenger's side of engine compartment, near strut tower. (Scheme 587) Go to next step.
4. Start engine and note engine speed. After engine speed is kept at 900-1300 RPM for 10 seconds, ensure engine returns to idle speed. Turn ignition off.
5. Remove "V" bank cover located on top of engine (if necessary) and disconnect air assist hose from air pipe. (Scheme 600) Air assist hose fits between IAC valve and air pipe. Place plug on end of air pipe and air assist hose. Place plug on end of air assist hose. Go to next step.
6. Start engine and note idle speed. Idle speed should be 500 RPM or less which may cause the engine to stall. Turn ignition off. If idle speed is not 500 RPM or less, check for air leak between air assist hoses, air pipe and fuel injectors. Remove plugs and jumper wire. Reconnect air assist hose.

Scheme 600

1. Start engine. Warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-133194-S24824673952002021900000) in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
2. Turn ignition off. Apply parking brake and place transmission/transaxle in Neutral. Ensure A/C is off.
3. Note location of data link connector No. 3 at driver's side of instrument panel. (Scheme 406) Install Jumper Wire (SST 09843-18040) between terminals No. 4 (CG) and 13 (TC) on data link connector No. 3. (Scheme 594) Go to next step.
4. Start engine and note engine speed. After engine speed is kept at 900-1300 RPM for 10 seconds, ensure engine returns to idle speed. Turn ignition off.
5. Disconnect air assist hose from IAC valve. (Scheme 601) Place plug on end of air assist hose. Go to next step.
6. Start engine and note idle speed. Idle speed should be 500 RPM or less which may cause the engine to stall. Turn ignition off. If idle speed is not 500 RPM or less, check for air leak between air assist hoses, air pipe and fuel injectors. Remove plug and jumper wire. Reconnect air assist hose.

Scheme 601

THROTTLE BODY

Note. Electronic Throttle Control System (ETCS) is used for controlling idle speed. ETCS consists of throttle body, accelerator pedal position sensor, Throttle Position (TP) sensor, throttle control motor, magnetic clutch and Engine Control Module (ECM).

1. Electronic Throttle Control System (ETCS) is used for controlling idle speed. ETCS consists of throttle body, accelerator pedal position sensor, Throttle Position (TP) sensor, throttle control motor and Engine Control Module (ECM).
2. To test operation of throttle control motor, turn ignition on. Depress accelerator pedal to operate accelerator pedal position sensor while listing for operating sound at throttle control motor and note that no grinding noise is heard at throttle control motor and throttle body. Accelerator pedal position sensor is located near top of accelerator pedal and throttle control motor is located on the throttle body. (Scheme 602)and (Scheme 603).
3. If throttle control motor operating sound is heard, go to next step. If throttle control motor operating sound is not heard, throttle control motor, wiring harness or ECM may be defective. ECM is located on behind glove box. For illustration of ECM location (Scheme 182) For wiring of throttle control motor, see ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. For testing of throttle control motor, go to step 7.
4. To test operation of Throttle Position (TP) sensor (if equipped), turn ignition off. Connect Toyota hand-held tester or scan tool to data link connector No. 3 at driver's side of instrument panel. (Scheme 384) Turn ignition on. Hand-held tester or scan tool is used to read throttle valve opening which is displayed as a percentage. Ensure Malfunction Indicator Light (MIL) on instrument panel is not illuminated. MIL is displayed as an engine icon. If MIL is not illuminated, go to next step. If MIL is illuminated, a Diagnostic Trouble Code (DTC) may be stored in ECM. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.
5. Read throttle valve opening on hand-held tester or scan tool by accessing THROTTLE POS under CURRENT DATA. Throttle valve opening should be 60 percent or more. Turn ignition off. If throttle valve opening is 60 percent or more, go to next step. If throttle valve opening is not at least 60 percent, problem may exist in TP sensor, wiring circuit or ECM. For testing of TP sensor, go to step 8.
6. To test operation of accelerator pedal position sensor, ensure ignition is on. Using Toyota hand-held tester or scan tool, read voltage of TP sensor by CURRENT DATA. Voltage should.6-1.0 volts. Turn ignition off. If voltage is not within specification, it may be necessary to check accelerator pedal position sensor. See «ACCELERATOR PEDAL POSITION SENSOR»(ref-151979-S07350329902003010900000) under ENGINE SENSORS & SWITCHES.
7. To test throttle control motor, disconnect electrical connector at throttle control motor on throttle body. (Scheme 602)and (Scheme 603). Note terminal identification on throttle body for throttle control motor. (Scheme 604)and (Scheme 605). Using ohmmeter, check resistance between M+ and M- terminals on throttle body for throttle control motor. Resistance should be.3-100.0 ohms at 68°F (20°C). If resistance is within specification, reinstall electrical connector. If resistance is not within specification, replace throttle body with throttle control motor as an assembly. See «THROTTLE BODY»(ref-133227-S01273866582002021900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article.
8. To test Throttle Position (TP) sensor (if equipped), disconnect electrical connector from TP sensor located on throttle body. (Scheme 602) Note terminal identification on TP sensor. (Scheme 606) Using ohmmeter, check resistance between VC and E2 terminals on TP sensor. Replace TP sensor if resistance is not 1200-3200 ohms at 68°F (20°C). See «THROTTLE BODY»(ref-133227-S01273866582002021900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article.

Scheme 602

Scheme 603

Scheme 604

Scheme 605

Scheme 606

For throttle body inspection procedure (Scheme 607)and (Scheme 608). To inspect accelerator position sensor wiring, see ACCELERATOR PEDAL POSITION SENSOR under ENGINE SENSORS & SWITCHES. To inspect throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES. To remove throttle body, see THROTTLE BODY under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 607

Scheme 608

For throttle body inspection procedure (Scheme 609)and (Scheme 610). To inspect accelerator position sensor wiring, see ACCELERATOR PEDAL POSITION SENSOR under ENGINE SENSORS & SWITCHES. To inspect throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES. To remove throttle body, see THROTTLE BODY under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 609

Scheme 610

Tacoma With ETCS

For throttle body inspection procedure (Scheme 611)and (Scheme 612). To remove throttle body, see THROTTLE BODY under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 611

Scheme 612

For throttle body inspection procedure (Scheme 613)and (Scheme 614). To remove throttle body, see THROTTLE BODY under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 613

Scheme 614

For throttle body inspection procedure (Scheme 615)and (Scheme 616). To inspect accelerator position sensor wiring, see ACCELERATOR PEDAL POSITION SENSOR under ENGINE SENSORS & SWITCHES. To remove accelerator position sensor, see ACCELERATOR PEDAL POSITION SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION. To inspect throttle position sensor, see THROTTLE POSITION SENSOR under ENGINE SENSORS & SWITCHES. To remove throttle position sensor, see THROTTLE BODY under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8.

Scheme 615

Scheme 616

For throttle body inspection procedure (Scheme 617)and (Scheme 618). To check throttle control motor (Scheme 619) To inspect accelerator position sensor wiring, see ACCELERATOR PEDAL POSITION SENSOR under ENGINE SENSORS & SWITCHES.

Scheme 617

Scheme 618

Scheme 619

For throttle body inspection procedure (Scheme 620)and (Scheme 621). To check throttle control motor (Scheme 622) To inspect accelerator position sensor wiring, see ACCELERATOR PEDAL POSITION SENSOR under ENGINE SENSORS & SWITCHES.

Scheme 620

Scheme 621

Scheme 622

IGNITION SYSTEMS

Note. For basic ignition checks, see IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

Knock Sensors

See KNOCK SENSOR under ENGINE SENSORS & SWITCHES.

EXHAUST GAS RECIRCULATION SYSTEM

Note. Applies for Camry models produced up to January 2003.

System Check (Camry & Camry Solara)

Manufacturer does not list an EGR system check, only individual component testing is listed. If a problem exists in EGR system, a Diagnostic Trouble Code (DTC) P0401, P0402, P0405 or P0409 may be stored in Engine Control Module (ECM). On Camry, DTC P0406 may also be used. On all models, see TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

EGR Gas Temperature Sensor (Camry & Camry Solara)

See EGR GAS TEMPERATURE SENSOR under ENGINE SENSORS & SWITCHES.

EGR Position Sensor (Camry & Camry Solara)

Note. EGR position sensor may also be referred to as EGR valve position sensor.

1. Disconnect electrical connector at EGR position sensor. EGR position sensor is located on top of EGR valve. (Scheme 623)
2. Using ohmmeter, check resistance between terminals E2 and VC on EGR position sensor. (Scheme 623) Resistance should be 1500-4300 ohms. If resistance is within specification, reinstall electrical connector on EGR position sensor and go to next step. If resistance is not within specification, replace EGR position sensor. See «EGR POSITION SENSOR»(ref-151984-S34046477842003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article.
3. To test EGR position sensor output voltage, disconnect vacuum hose from EGR valve. Remove glove box for access to Engine Control Module (ECM). Turn ignition on. Using voltmeter, check voltage between ECM terminals E2 (Brown wire) and VC (Yellow wire). (Scheme 624)and (Scheme 625). Voltage should be 4.5-5.5 volts. Remove voltmeter.
4. Connect voltmeter between ECM terminals E2 (Brown wire) and EGLS (White/Green wire). (Scheme 626)and (Scheme 627). Using vacuum pump, apply 5.1 in. Hg of vacuum to EGR valve and note voltage. Voltage should be 3.2-5.1 volts with vacuum applied on EGR valve. Release vacuum from EGR valve and note voltage. Voltage should be.4-1.6 volts with vacuum released from EGR valve. Replace EGR position sensor if voltage is not within specification. See «EGR POSITION SENSOR»(ref-151984-S34046477842003010900000) under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - V6 & V8 article. Remove vacuum pump and reinstall vacuum hose on EGR valve.

Scheme 623

Scheme 624

Scheme 625

Scheme 626

Scheme 627

EGR Vacuum Control Valve (Camry & Camry Solara)

Note. EGR vacuum control valve may also be referred to as EGR VCV.

1. Disconnect vacuum hoses and remove EGR vacuum control valve. EGR vacuum control valve is located on top of engine, near EGR valve. see scheme 468and see scheme 470.
2. Plug port "Z" and connect vacuum pump to port "S" on EGR vacuum control valve. (Scheme 628)
3. Using vacuum pump, apply 11.8 in. Hg of vacuum to EGR vacuum control valve. Vacuum pump should be operated 3 times so applied vacuum on EGR vacuum control valve remains at 8.6-11.8 in. Hg of vacuum.
4. Stop operating the vacuum pump after 3 times and note vacuum reading. Vacuum reading should decrease to 4.4-7.1 in. Hg of vacuum after 10 seconds. Replace EGR vacuum control valve if vacuum reading is not within specification.

Scheme 628

EGR Vacuum Switching Valve (Camry & Camry Solara)

1. Remove "V" bank cover and emission control valve set located on top of engine for access to EGR Vacuum Switching Valve (VSV). (Scheme 201)and (Scheme 203).
2. Remove EGR VSV. Using ohmmeter, ensure continuity exists between electrical terminals on EGR VSV and resistance is 27-33 ohms at 68°F (20°C). Replace EGR VSV if no continuity exists or resistance is not within specification.
3. Using ohmmeter, ensure no continuity exists between each electrical terminal and body of EGR VSV. Replace EGR VSV if continuity exists between electrical terminal and body of EGR VSV.
4. To test EGR VSV operation, apply air pressure to port "E". Ensure air flows from port "G". Perform STEP 1 in illustration. (Scheme 629)
5. Apply battery voltage and ground to electrical terminals on EGR VSV. Apply air pressure to port "E". Ensure air flows from port "F" and not from port "G". Perform STEP 2 in illustration. (Scheme 629) Replace EGR VSV if defective. Reinstall EGR VSV.

Scheme 629

EGR Valve (Camry & Camry Solara)

1. Remove EGR valve. See «EGR VALVE»(ref-151984-S15585781522003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article.
2. Inspect EGR valve for restricted passages caused by carbon deposits. Using vacuum pump, apply vacuum directly to EGR valve and ensure valve opens. Release vacuum and ensure valve closes. Replace EGR valve if defective.

FUEL EVAPORATIVE SYSTEM

Note. Fuel evaporative system is referred to as fuel EVAP system and may contain different components depending on application. see scheme 467- see scheme 479. When testing fuel EVAP system components, use proper illustration to determine component location.

Note. An On-Board Refilling Vapor Recovery (ORVR) system is used to recover fuel vapors into charcoal canister that are generated during refueling. ORVR system consists of fuel inlet pipe, overfill check valve, cut-off valve and charcoal canister. Overfill check valve may also be referred to as On-Board Refueling Vapor Recovery Overfill Check Valve (ORVR-OCKV) or fill check valve. Cut-off valve may also be referred to On-Board Refueling Vapor Recovery Cut-Off Valve (ORVR-COV). For testing of fuel EVAP system and ORVR system, see appropriate FUEL EVAP SYSTEM TEST.

Note. Charcoal canister may also be referred to as EVAP canister. Manufacturer provides testing information for testing airtightness of fuel tank and components along with testing of charcoal canister and fuel EVAP system.

Canister Closed Valve Vacuum Switching Valve (Avalon, Camry, Camry Solara, Highlander & Sienna)

1. Disconnect electrical connector at Canister Closed Valve Vacuum Switching Valve (CCV VSV). CCV VSV is located on air cleaner housing. see scheme 467- see scheme 471 and see scheme 474.
2. Remove CCV VSV. Using ohmmeter, check that continuity exists between electrical terminals on CCV VSV and that resistance is within specification. See «CCV VSV RESISTANCE»(ref-151979-S15041635522002021900000) table. Replace CCV VSV if no continuity exists or resistance is not within specification.
3. Ensure no continuity exists between each electrical terminal and body of CCV VSV. Replace CCV VSV if continuity exists between electrical terminal and body of CCV VSV.
4. To test CCV VSV operation, apply air pressure to port "A". Ensure air flows from port "B". Perform STEP 1 in illustration. (Scheme 630)- (Scheme 631).
5. Apply battery voltage and ground to electrical terminals on CCV VSV. Apply air pressure to port "A". Ensure air does not flow from port "B". Perform STEP 2 in illustration. (Scheme 630)- (Scheme 631). Replace CCV VSV if defective.

CCV VSV RESISTANCE

Scheme 630

Scheme 631

Canister Closed Valve Vacuum Switching Valve (Land Cruiser & Sequoia)

1. Disconnect electrical connector at Canister Closed Valve Vacuum Switching Valve (CCV VSV). CCV VSV is located on bracket at driver's side of engine compartment, just to the rear of fuse/relay box. see scheme 472and see scheme 473.
2. Remove CCV VSV. Using ohmmeter, check that continuity exists between electrical terminals on CCV VSV and that resistance is within specification. Resistance should be approximately 24-30 ohms. Replace CCV VSV if no continuity exists or resistance is not within specification.
3. Ensure no continuity exists between each electrical terminal and body of CCV VSV. Replace CCV VSV if continuity exists between electrical terminal and body of CCV VSV.
4. To test CCV VSV operation, apply air pressure to port "A". Ensure air flows from port "B". Perform STEP 1 in illustration. (Scheme 632)
5. Apply battery voltage and ground to electrical terminals on CCV VSV. Apply air pressure to port "A". Ensure air does not flow from port "B". Perform STEP 2 in illustration. (Scheme 632) Replace CCV VSV if defective.

CCV VSV RESISTANCE

Scheme 632

Canister Closed Valve Vacuum Switching Valve (Tacoma)

1. Disconnect electrical connector at Canister Closed Valve Vacuum Switching Valve (CCV VSV). On Tacoma, CCV VSV is located in engine compartment, on bracket bolted to inside of driver's side front fender panel. see scheme 475
2. Remove CCV VSV. Using ohmmeter, check that continuity exists between electrical terminals on CCV VSV and that resistance is within specification. Resistance should be 25-30 ohms at 68°F (20°C) and 33-42 ohms at 248°F (120°C). Replace CCV VSV if no continuity exists or resistance is not within specification.
3. Ensure no continuity exists between each electrical terminal and body of CCV VSV. Replace CCV VSV if continuity exists between electrical terminal and body of CCV VSV.
4. To test CCV VSV operation, apply air pressure to port "A". Ensure air flows from port "B". Perform STEP 1 in illustration. (Scheme 633)
5. Apply battery voltage and ground to electrical terminals on CCV VSV. Apply air pressure to port "A". Ensure air does not flow from port "B". Perform STEP 2 in illustration. (Scheme 633) Replace CCV VSV if defective.

Scheme 633

Canister Closed Valve Vacuum Switching Valve (Tundra & 4Runner)

Note. On 4Runner models, if CCV VSV is not operating as specified in procedure, replace charcoal canister.

For canister closed valve vacuum switching valve test (Scheme 634)

Scheme 634

Charcoal Canister (Avalon & Camry Solara)

For testing of charcoal canister, see FUEL EVAP SYSTEM TEST (AVALON & CAMRY SOLARA) .

Charcoal Canister (Camry)

For testing of charcoal canister (Scheme 635)- (Scheme 636).

Scheme 635

Scheme 636

Charcoal Canister (Highlander)

For testing of charcoal canister (Scheme 637)- (Scheme 638).

Scheme 637

Scheme 638

Charcoal Canister (Land Cruiser & Sequoia)

For testing of charcoal canister, see FUEL EVAP SYSTEM TEST (LAND CRUISER & SEQUOIA) .

Charcoal Canister (Sienna)

For testing of charcoal canister, see FUEL EVAP SYSTEM TEST (SIENNA) .

Charcoal Canister (Tacoma)

For testing of charcoal canister, see FUEL EVAP SYSTEM TEST (TACOMA) .

Charcoal Canister (Tundra)

For testing of charcoal canister, see FUEL EVAP SYSTEM TEST (TUNDRA) .

Charcoal Canister (4Runner)

For testing of charcoal canister (Scheme 639)- (Scheme 641).

Scheme 639

Scheme 640

Scheme 641

Cut-Off Valve

Individual component testing is not available from manufacturer. Manufacturer provides testing information for testing airtightness of fuel tank and components along with testing of charcoal canister, cut-off valve and fuel EVAP system. See appropriate FUEL EVAP SYSTEM TEST.

EVAP Vacuum Switching Valve (All Models)

1. Remove EVAP Vacuum Switching Valve (VSV). For location of EVAP VSV, see «EVAP VSV LOCATIONS»(ref-151979-S27030012692002021900000) table and see scheme 467 - see scheme 479.
2. Using ohmmeter, ensure continuity exists between electrical terminals on EVAP VSV and that resistance is within specification. See «EVAP VSV RESISTANCE»(ref-151979-S39448775662002021900000) table. Replace EVAP VSV if no continuity exists or resistance is not within specification.
3. Using ohmmeter, ensure no continuity exists between each electrical terminal and body of EVAP VSV. Replace EVAP VSV if continuity exists between electrical terminal and body of EVAP VSV.
4. To test EVAP VSV operation, apply air pressure to port "E". Ensure air does not flow from port "F". Perform STEP 1 in illustration. (Scheme 642)- (Scheme 646).
5. Apply battery voltage and ground to electrical terminals on EVAP VSV. Apply air pressure to port "E". Ensure air flows from port "F". Perform STEP 2 in illustration. (Scheme 642)- (Scheme 646). Replace EVAP VSV if defective.

EVAP VSV LOCATIONS

EVAP VSV RESISTANCE

Scheme 642

Scheme 643

Scheme 644

Scheme 645

Scheme 646

Overfill Check Valve

Individual component testing is not available from manufacturer. Manufacturer provides testing information for testing airtightness of fuel tank and components along with testing of charcoal canister, overfill check valve and fuel EVAP system. See appropriate FUEL EVAP SYSTEM TEST.

Pressure Switching Valve Vacuum Switching Valve (Avalon, Camry, Camry Solara, Highlander, Land Cruiser, Sequoia, Sienna & Tacoma)

1. Remove pressure switching valve Vacuum Switching Valve (VSV). For pressure switching valve VSV location, see «PRESSURE SWITCHING VALVE VSV LOCATION»(ref-151979-S36916177292002021900000) table and see scheme 467 - see scheme 479.
2. Remove pressure switching valve Vacuum Switching Valve (VSV).
3. Using ohmmeter, ensure continuity exists between electrical terminals on pressure switching valve VSV and that resistance is within specification. See «PRESSURE SWITCHING VALVE VSV RESISTANCE»(ref-151979-S29173549662002021900000) table. Replace pressure switching valve VSV if no continuity exists or resistance is not within specification.
4. Ensure no continuity exists between each electrical terminal and body of pressure switching valve VSV. Replace pressure switching valve VSV if continuity exists between electrical terminal and body of pressure switching valve VSV.
5. To test pressure switching valve VSV operation, apply air pressure to port "E". Ensure air does not flow from port "F". Perform STEP 1 in illustration. (Scheme 647)and (Scheme 648).
6. Apply battery voltage and ground to electrical terminals on pressure switching valve VSV. Apply air pressure to port "E". Ensure air flows from port "F". Perform STEP 2 in illustration. (Scheme 647)and (Scheme 648). Replace pressure switching valve VSV if defective.

PRESSURE SWITCHING VALVE VSV LOCATION

PRESSURE SWITCHING VALVE VSV RESISTANCE

Scheme 647

Scheme 648

Vapor Pressure Sensor (Avalon)

For testing of vapor pressure sensor (Scheme 649)

Scheme 649

Vapor Pressure Sensor (Camry-Up To Jan. 2003 Production)

For testing of vapor pressure sensor (Scheme 650)and (Scheme 651). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 650

Scheme 651

Vapor Pressure Sensor (Camry-Jan. 2003 & Later Production)

For testing vapor pressure sensor (Scheme 652)and (Scheme 653). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 652

Scheme 653

Vapor Pressure Sensor (Camry Solara)

For testing of vapor pressure sensor (Scheme 654)

Scheme 654

Vapor Pressure Sensor (Highlander)

For testing of vapor pressure sensor (Scheme 655)and (Scheme 656). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 655

Scheme 656

Vapor Pressure Sensor (Land Cruiser)

For testing of vapor pressure sensor (Scheme 657)

Scheme 657

Vapor Pressure Sensor (Sequoia)

For testing of vapor pressure sensor (Scheme 658)

Scheme 658

Vapor Pressure Sensor (Sienna)

For testing of vapor pressure sensor (Scheme 659)

Scheme 659

Vapor Pressure Sensor (Tacoma)

For testing of vapor pressure sensor (Scheme 660)

Scheme 660

Vapor Pressure Sensor (Tundra 3.4L)

For testing of vapor pressure sensor (Scheme 661)

Scheme 661

Vapor Pressure Sensor (Tundra 4.7L)

For testing of vapor pressure sensor (Scheme 662)

Scheme 662

Vapor Pressure Sensor (4Runner 4.0L)

For testing of vapor pressure sensor (Scheme 663)

Scheme 663

Vapor Pressure Sensor (4Runner 4.7L)

For testing of vapor pressure sensor (Scheme 664)and (Scheme 665).

Scheme 664

Scheme 665

Avalon, Camry, Camry Solara, Highlander, Land Cruiser, Sequoia, Sienna, Tundra 4.7L & 4Runner

1. Remove Positive Crankcase Ventilation (PCV) valve. See «PCV VALVE LOCATION»(ref-151979-S11850631132003010900000) table.
2. Apply air pressure to PCV valve at bottom (cylinder head side) of PCV valve. Ensure air flows easily through PCV valve. Apply air pressure to PCV valve at vacuum side (intake manifold side) of PCV valve. Ensure air flows through PCV valve with some resistance. Replace PCV valve if valve does not function as described.

1. Positive Crankcase Ventilation (PCV) valve. See «PCV VALVE LOCATION»(ref-151979-S11850631132003010900000) table.
2. Apply air pressure to PCV valve at bottom (cylinder head side) of PCV valve. Ensure air flows easily through PCV valve. Apply air pressure to PCV valve at vacuum side (intake manifold side) of PCV valve. Ensure air flows through PCV valve with some resistance.
3. Apply air pressure to PCV valve at vacuum side (intake manifold side) of PCV valve while using small screwdriver to push upward on valve located inside PCV valve at bottom (cylinder head side) of PCV valve. Ensure air flows through PCV valve with strong resistance. Replace PCV valve if valve does not function as described.

PCV VALVE LOCATION

1. Start engine. Warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-151949-S04785361952003010900000) in ON-VEHICLE ADJUSTMENTS - V6 & V8 article. Shut engine off. Remove cap, filter and separator from dashpot on throttle body. (Scheme 666)
2. Start engine. Maintain engine speed at 2500 RPM. Plug Vacuum Transmitting Valve (VTV) hole in dashpot with your finger. (Scheme 667)
3. Release throttle. Dashpot should be extended and dashpot setting RPM should be 1800-2200 RPM. If dashpot setting RPM is not within specification, rotate dashpot adjusting screw to obtain correct RPM. (Scheme 668)
4. Remove finger from VTV hole in dashpot. Ensure engine returns to proper idle speed in approximately one second. Install separator, filter and cap. Ensure filter is installed with the coarse surface facing outward (away from dashpot).

Scheme 666

Scheme 667

Scheme 668

Note. Electronic Throttle Control System (ETCS) may also be referred to as Electronic Throttle Control System-Intelligent (ETCS-I or ETCS-i).

For testing of throttle body and components, see THROTTLE BODY under IDLE CONTROL SYSTEMS.

Avalon, Camry Solara, Sienna & Tacoma Without ETCS

1. Start engine. Warm engine to normal operating temperature. Ensure idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-151949-S04785361952003010900000) in ON-VEHICLE ADJUSTMENTS - V6 & V8 article.
2. Shut engine off. Disconnect and plug vacuum hose at throttle opener near throttle body. (Scheme 669)- (Scheme 671). Start engine and note engine speed. Engine speed should be within specification. See «THROTTLE OPENER SPECIFICATIONS»(ref-151979-S15814936992003010900000) table.
3. If engine speed is not within specification, replace throttle body. See «THROTTLE BODY»(ref-151984-S20444146202003010900000) under FUEL SYSTEMS in REMOVAL & INSTALLATION - V6 & V8 article. Shut engine off. Reinstall vacuum hose on throttle opener. Start engine and ensure engine returns to proper idle speed.

THROTTLE OPENER SPECIFICATIONS (1)

Scheme 669

Scheme 670

Scheme 671

VARIABLE VALVE TIMING SYSTEM

Note. Variable Valve Timing (VVT) system is used on Avalon, Camry (January 2003 and later production), Highlander, Sienna and 4Runner 4.0L V6. If problem exists in VVT system, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.

Avalon, Camry, Highlander, Sienna & 4Runner 4.0L V6

Variable Valve Timing (VVT) sensor may also be referred to as camshaft position sensor. For testing camshaft position sensor, see CAMSHAFT POSITION SENSOR under IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - V6 & V8 article.

VARIABLE VALVE TIMING CAMSHAFT TIMING OIL CONTROL VALVE

Note. Variable Valve Timing (VVT) camshaft timing oil control valve may also be referred to as oil control valve for VVT, VVT Oil Control Valve (OCV) or camshaft timing oil control valve VVT.

Avalon, Camry (Jan. 2003 & Later Production), Highlander & Sienna

1. Remove "V" bank cover on top of engine for access to VVT camshaft timing oil control valves. VVT camshaft timing oil control valves are located on end of cylinder head at flywheel end of engine. (Scheme 672)
2. To check VVT camshaft timing oil control valve resistance, disconnect electrical connector at appropriate VVT camshaft timing oil control valve. Using ohmmeter, check resistance between electrical terminals on VVT camshaft timing oil control valve. Resistance should be 6.9-7.9 ohms at 68°F (20°C). If resistance is within specification, go to next step. If resistance is not within specification, replace VVT camshaft timing oil control valve.
3. To check VVT camshaft timing oil control valve operation, remove retaining bolt and appropriate VVT camshaft timing oil control valve with "O" ring from cylinder head. Note movement of the valve inside VVT camshaft timing oil control valve while applying and disconnecting battery voltage and ground to terminals No. 1 and 2 on VVT camshaft timing oil control valve. Valve should move outward toward end of assembly opposite electrical connector with voltage applied and should move inward toward electrical connector end of assembly with voltage not applied. (Scheme 673) Replace VVT camshaft timing oil control valve if operation is not as specified. Reinstall VVT camshaft timing oil control valve using NEW "O" ring. On Avalon and Sienna, tighten retaining bolt to 66 INCH lbs. (7.5 N.m). On Camry and Highlander, tighten retaining bolt to 71 INCH lbs. (8.0 N.m).

Scheme 672

Scheme 673

4Runner 4.0L V6

1. For access to VVT camshaft timing oil control valves, remove air intake chamber and fuel rails. See «VARIABLE VALVE TIMING CAMSHAFT TIMING OIL CONTROL VALVE»(ref-151984-S08365083522003010900000) under VARIABLE VALVE TIMING SYSTEM in REMOVAL & INSTALLATION - V6 & V8 article for air intake chamber and fuel rail removal.
2. To check VVT camshaft timing oil control valve resistance, disconnect electrical connector at appropriate VVT camshaft timing oil control valve. Using ohmmeter, check resistance between electrical terminals on VVT camshaft timing oil control valve. Resistance should be 6.9-7.9 ohms at 68°F (20°C). If resistance is within specification, go to next step. If resistance is not within specification, replace VVT camshaft timing oil control valve.
3. To check VVT camshaft timing oil control valve operation, remove retaining bolt and appropriate VVT camshaft timing oil control valve with "O" ring from cylinder head. Note movement of the valve inside VVT camshaft timing oil control valve while applying and disconnecting battery voltage and ground to terminals No. 1 and 2 on VVT camshaft timing oil control valve. Valve should move outward toward end of assembly opposite electrical connector with voltage applied and should move inward toward electrical connector end of assembly with voltage not applied. (Scheme 674)Replace VVT camshaft timing oil control valve if operation is not as specified. Reinstall VVT camshaft timing oil control valve using NEW "O" ring. Tighten retaining bolt to 80 INCH lbs. (9 N.m).

Scheme 674

1. Manufacturer does not provide complete system testing, only individual components. To test the active control engine mount, note location active control engine mount at the front (radiator side) of the engine, just below exhaust manifold. (Scheme 675) Manufacturer lists testing procedure for active control engine mount with the mount assembly removed.
2. Disconnect vacuum hose from vacuum fitting on active control engine mount and connect vacuum pump to vacuum fitting. (Scheme 676) Using vacuum pump, apply 25.0 in. Hg of vacuum to active control engine mount for at least one minute and check that no change exists in the needle movement. Needle is located at the bottom of active engine control mount. Check for signs of fluid leakage on active engine mount. If active control engine mount does not operate as specified or signs of fluid leakage exist, replace active control engine mount.
3. To test Active Control Mount Vacuum Switching Valve (ACM VSV), remove ACM VSV. ACM VSV is located near active control engine mount at the front (radiator side) of the engine, just below exhaust manifold. (Scheme 675) Using ohmmeter, check that continuity exists between electrical terminals on ACM VSV and that resistance is 19-21 ohms at 68°F (20°C). If continuity exists and resistance is within specification, go to next step. If no continuity exists or resistance is not within specification, replace ACM VSV.
4. Using ohmmeter, ensure no continuity exists between each electrical terminal and body of ACM VSV. If continuity does not exist between electrical terminal and body of ACM VSV, go to next step. If continuity exists between electrical terminal and body of ACM VSV, replace ACM VSV.
5. To check ACM VSV operation, apply air pressure to port "G" on ACM VSV. Ensure air flows from ports "E" and "H". Perform STEP 1 in illustration. (Scheme 677) Apply battery voltage and ground to electrical terminals on ACM VSV. Apply air pressure to port "F" on ACM VSV. Ensure air flows from ports "E" and "H". Perform STEP 2 in illustration. (Scheme 677) If ACM VSV operates properly, reinstall ACM VSV. If ACM VSV does not operate properly, replace ACM VSV.
6. To test vacuum tank, disconnect hoses from vacuum tank. Vacuum tank is located near driver's side front corner of engine compartment, below battery tray. Apply air pressure to port "B" on vacuum tank. Ensure air flows from port "A". Perform STEP 1 in illustration. see scheme 575 Apply air pressure to port "A". Ensure air does not flow from port "B". Perform STEP 2 in illustration. see scheme 575
7. Plug port "B". Using vacuum pump, apply 7.9 in. Hg of vacuum to port "A". Perform STEP 3 in illustration. see scheme 575 Ensure vacuum reading will hold for at least one minute. If vacuum tank is okay, reconnect vacuum hoses. If vacuum tank is defective, replace vacuum tank.

Scheme 675

Scheme 676

Scheme 677

For active control engine mount test (Scheme 678)- (Scheme 682). Before replacing ECM, check ECM connectors and ground circuits. See ENGINE CONTROL MODULE POWER & GROUND CIRCUITS under COMPUTERIZED ENGINE CONTROLS.

Scheme 678

Scheme 679

Scheme 680

Scheme 681

Scheme 682

1. Check vacuum hoses for active control engine mount system for looseness, damage, restrictions or being disconnected. (Scheme 683) Ensure cap is installed on end of vacuum hose "C". If cap is missing from vacuum hose "C" or vacuum hose "C" is damaged, replace vacuum hose "C" as an assembly. DO NOT repair this vacuum hose by cutting and splicing in another vacuum hose. If all vacuum hoses and connections are okay, go to next step. If vacuum hoses and connections are defective, repair or replace components as necessary.
2. Start engine. Warm engine to normal operating temperature. Connect Toyota hand-held tester to data link connector No. 3 at driver's side of instrument panel. (Scheme 396) Turn hand-held tester on. Select ACM INHIBIT ACTIVE TEST on hand-held tester. Place transaxle in Park or Neutral. Check whether or not engine vibration increases while ACM INHIBIT ACTIVE TEST is in the ON state. If engine vibration increases while ACM INHIBIT ACTIVE TEST is in the ON state, shut engine off. Remove hand-held tester. Go to next step. If engine vibration does not increase while ACM INHIBIT ACTIVE TEST is in the ON state, shut engine off. Remove hand-held tester. Go to step 4.
3. Start engine. Warm engine to normal operating temperature. Chock all 4 wheels and apply parking brake. Depress brake and place transaxle in Drive. Disconnect vacuum hose "A" at upper cap on air cleaner assembly. (Scheme 683) Place your finger over end of disconnected vacuum hose "A" and check that suction exists intermittently. If suction does not exist intermittently, shut engine off. Reinstall vacuum hose "A" on upper cap on air cleaner assembly. Go to next step. If suction exists intermittently, shut engine off. Reinstall vacuum hose "A" on upper cap on air cleaner assembly. Active control engine mount system is operating properly.
4. Remove glove box for access to Engine Control Module (ECM). For illustration of ECM location (Scheme 172) Connect oscilloscope leads between terminal ACM1 (Black wire) on ECM electrical connector E7 and terminal E1 (Brown wire) on ECM electrical connector E8. (Scheme 684)
5. Start engine. Warm engine to normal operating temperature. Apply parking brake. Note voltage reading on oscilloscope with transaxle in proper gear position and in accordance with engine speed. See «VOLTAGE SPECIFICATIONS»(ref-151979-S30842155732003010900000) table. If voltage is not as specified, shut engine off. Remove oscilloscope. Go to next step. If voltage is as specified, shut engine off. Remove oscilloscope. Go step 11.
6. Disconnect electrical connector at Active Control Mount Vacuum Switching Valve (ACM VSV). ACM VSV is located near active control engine mount at the front (radiator side) of the engine, just below exhaust manifold. (Scheme 683) Using ohmmeter, check resistance between electrical terminals on ACM VSV. Resistance should be 19-21 ohms at 68°F (20°C). If resistance is within specification, go to next step. If resistance is not within specification, replace ACM VSV.
7. Ensure electrical connector at ACM VSV is still disconnected. Remove EFI main relay from fuse/relay box at driver's side front corner of engine compartment. (Scheme 685) EFI main relay may also be referred to as EFI relay. To check for open in wiring between EFI main relay and ACM VSV, using ohmmeter, check resistance between cavity No. 3 (Black/White wire) in fuse/relay box for EFI main relay and terminal No. 1 (Black/White wire) on electrical connector for ACM VSV. Use care not to damage cavity for EFI main relay by applying excessive force on cavity when checking resistance. If resistance is one ohm or less, go to next step. If resistance is more than one ohm, repair open on Black/White wire between EFI main relay and ACM VSV. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
8. To check for short in wiring between EFI main relay output circuit and ground, using ohmmeter, check for continuity between cavities No. 2 (White/Black wire) and No. 3 (Black/White wire) in fuse/relay box for EFI main relay. (Scheme 685) Use care not to damage cavities for EFI main relay by applying excessive force on cavity when checking for short. If no continuity exists, go to next step. If continuity exists, repair short to in EFI main relay output circuit and ground between cavities No. 2 (White/Black wire) and No. 3 (Black/White wire) in fuse/relay box for EFI main relay. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
9. Ensure ignition is off. Disconnect ECM electrical connector E7. (Scheme 684) To check for open in wiring between ECM and ACM VSV, using ohmmeter, check resistance between terminal ACM1 (Black wire) on ECM electrical connector E7 and terminal No. 2 (Black wire) on ACM VSV electrical connector. (Scheme 684)and (Scheme 685). If resistance is one ohm or less, go to next step. If resistance is more than one ohm, repair open on Black wire between ECM and ACM VSV. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
10. To check for short in wiring between ECM and ACM VSV, using ohmmeter, check for continuity between terminal ACM1 (Black wire) on ECM electrical connector E7 and terminal E1 (Brown wire) on ECM electrical connector E8. (Scheme 684) If continuity exists, repair short to ground in Black wire between ECM and ACM VSV. If no continuity exists, check ECM ground circuit. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If ECM ground circuit is okay, replace ECM. If ECM is replaced and vehicle is equipped with engine immobilizer system, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see «COMPUTER RELEARN PROCEDURES - TOYOTA»(ref-158393) article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
11. Remove Active Control Mount Vacuum Switching Valve (ACM VSV). ACM VSV is located near active control engine mount at the front (radiator side) of the engine, just below exhaust manifold. (Scheme 683) Apply air pressure to port "G" on ACM VSV. Ensure air flows from ports "E" and "H". Perform STEP 1 in illustration. (Scheme 677) Apply battery voltage and ground to electrical terminals on ACM VSV. Apply air pressure to port "F" on ACM VSV. Ensure air flows from ports "E" and "H". Perform STEP 2 in illustration. (Scheme 677) If ACM VSV operates properly, reinstall ACM VSV. Go to next step. If ACM VSV does not operate properly, replace ACM VSV.
12. Disconnect vacuum hose from vacuum fitting on active control engine mount and connect vacuum pump to vacuum fitting. (Scheme 686) Using vacuum pump, apply 25.0 in. Hg of vacuum to active control engine mount for at least one minute and check that no change exists is the needle movement. Needle is located at the bottom of active engine control mount. (Scheme 686) Check for signs of fluid leakage on active engine mount. If active control engine mount operates properly, active control engine mount system is operating properly. If active control engine mount does not operate as specified or signs of fluid leakage exist, replace active control engine mount.

VOLTAGE SPECIFICATIONS

Scheme 683

Scheme 684

Scheme 685

Scheme 686